Military or trade port cities? About the form and function of the Hispanic colonial cities in Latin America and the Caribbean

ABSTRACT
 This work studies urban form and function in Hispanic American colonial port cities. By combining different research questions and points of view, new insights are given into matters such as the origin of their urban grids, the development of their fortifications throughout the colonial era, and the military versus trade function they accomplished. The focus is on Cartagena de Indias, Colombia, with other Hispanic colonial cities also included in the discussion. The field work is based on primary literature about colonial laws and ordinances and the reports of several viceroys in the eighteenth century as well as a wide array of secondary literature in different languages. The results show that, while these cities fulfilled an important role as trade nodes, this function was second to their military role. However, both functions are found to be interdependent in a number of ways.

functions of these cities. We have delved into this matter and offer a chronological perspective featuring literature sources hitherto not considered for urban research, such as the reports by the viceroys (the highest colonial authorities) of New Granada (a vast region made up by today's Colombia, Venezuela, Ecuador and Panama) about the city of Cartagena de Indias in the eighteenth century. In fact, we contend that, in the Caribbean colonial cities, the military and trade functions were connected by the process of building, upkeeping and financing the walls, fortresses and castles that defended them.
Our field work consisted of research based on primary literature (legal texts, reports' transcriptions, maps, illustrations) and secondary literature about the topics pursued. As for the latter, authors writing in Spanish, French or Catalan have been given preference over the 'classical' English texts: works written in Latin languages are abundant and interesting, but quite unknown to international audiences, a gap this work tries to bridge as well. Thus, by cross-discussing the above research points and bringing in new documentary sources and authors, it is hoped to give new insights into crucial urban issues in colonial Latin America, offering a broad historical perspective across several centuries of urban development (See Supplemental Materials, Table B).
The city mainly researched in this article is Cartagena de Indias, on today's Caribbean coast of Colombia. There are several grounds for this choice: its central location in the Empire, connecting South America to Central America and the Caribbean, put it in a key position (Figure 1). Cartagena was also the guardian of the inland Andean regions, ultimately guaranteeing the safety of cities such as Bogota and Quito and, beyond them, the Viceroyalty of Peru, the jewel in its crown, with its silver and gold mines. 2 Consequently, it was one of the focuses in the colonial strategy. It is also an outstanding example of a Hispanic colonial city thanks to the urban and historic processes that took place during the colonial era. Its Historic Centre, one of the best preserved across the continent, keeps vivid traces of this past and therefore has been marked as a World Heritage site by UNESCO since 1984 (see also Supplemental Materials, Figure A).
However, while going deeper into one Hispanic port city, we also wish to underscore the broad context and importance of our research for other similar cities in the region. So, this research work is a 'case study' 3 which intends to be 'representative '. 4 Literature review: some contributions to the American colonial urban grid The 'two camps' in the discussion As for the discussion about the origin of the grid used in Hispanic America, quite diverging voices can be found in the literature. We divide them into two main camps: the 'physical' one, which looks for built environments that might have served as a model for the American cities, and the 'theoretical' one, which gives more importance to the ideas behind the colonial grid. Within each camp, however, there are differences of opinion. In the theoretical camp, for example, Kinsbruner just sees a growing influence of the Roman planer Vitruvius 5 ; Viforcos points to three sources: Vitruvius, the Christian thinkers such as St. Thomas and Eiximenis (see 2.2.), as well as the Roman urban influence. 6 Smith lists several sources of influence without weighing them up: Vitruvius, the Renaissance urban theories, the bastidas (see 2.2) and the town of Santa Fe de Granada, Spain (founded 1491). 7 In sum, it is hard to draw a conclusion along these lines.
The physical camp looks for specific places which transferred (parts of) their urban structures to America, thus challenging the basic assumption of the Catalano-Aragonese town model of 1300 as the main one implemented in the New World. So recent research argues that some outlines of the urban form put forth by the ordinacions may be found in the towns founded in the thirteenth century by King Alfonso in the lands of Castile. 8 Others look for even smaller areas as the origin of some urban ideas, such as the towns of Jaen, in today's southern Spain 9 or Jaca, in High Aragon 10 , underscoring the latter's influence on the bastidas and on northern Spain's towns along the Way of St. James. Within this camp, we also include the 'back shooters', i.e. those who look for influences of Hispanic America on planning in Spain in latter centuries, for example, in the nineteenth-century plan for Barcelona's Eixample [new town] by Ildefons Cerdà. 11 If we then add to this the researchers working comparatively to try to establish typologies 12 , one may end up with a confusing panorama.
To make things even harder for 'structuralist' research, there is an issue concerning early urban planning in the Atlantic archipelagos off Africa (Cape Verde, Canaries, Madeira, etc.). Some researchers point to the interest of these as a research field, possibly positing urban evolutive hypotheses, which would see an evolution from Southern Europe to colonial America via these islands. 13 We only point to this matter as another possible research line.

Late medieval urban ideas in southwestern Europe
This subsection briefly reviews three elements from medieval urban theory, which, to the authors' criteria, have not been sufficiently taken into account in the discussion as far as their influence in American urbanism is concerned. They can be summed up as the Occitan and Catalano-Aragonese sources of influence. Perhaps, as the colonization processes were carried out by France (in parts of North America) and Castile (in Central and South America), these more 'peripheral contributions' have been left in the background. They are: the French bastidas, the ordinacions of King James II and the philosophical influence of the friar Eiximenis.
In the thirteenth and fourteenth centuries, an urban grid model appeared across southern France: several hundreds of towns, known by the Occitan name bastidas, were founded. 14 Their functions varied from settling the territory to being 'border towns' on the edges of a duchy or a county. In their canonical form, the bastidas display a grid of streets intersecting at 90 degrees and a central square. They might have influenced the Iberian planned towns from 1250 onwards, mainly because of the geographical proximity between the Bearn and High Aragon regions. However, this remains an under researched issue. Mestre ponders that the bastidas had a stronger influence than has been considered to date, in the foundation of cities and towns across Mediterranean Europe from 1300 onwards 15 (Figures 2 and 3).
In the Catalano-Aragonese kingdom, King James II issued the ordinacions in 1300, a set of urban norms to indicate how the island of Majorca should be populated, as decades before it had been taken from the Moors. These norms took the planned grid as the basis for building new towns. 16 The norms were hugely influential, and in fact, there is a general consensus that the town plan favoured by the ordinacions was the one transferred to the Americas in the colonization process. In the Catalano-Aragonese kingdom, the three best-achieved towns under the ordinacions are considered to be Petra and Sa Pobla in Majorca and Vila-real in Valencia (Figures 4 and 5).
The third important source of influence in urban planning a bit later in that era, as far as the ideological component goes, are the thoughts by the Catalan friar Francesc Eiximenis. In 1384, he published his work La ciutat ideal o celestial de Jerusalem [The ideal or heavenly city of Jerusalem], 17 which would exert a remarkable influence on urban ideas in the Iberian kingdoms during the fifteenth century. 18 As part of a large collection of theological works he authored, this particular one sets out to justify how cities must be built and laid out: wide main streets, a strong precinct of walls, etc. Thus, he gave the ideological basis to the towns built under the ordinacions rules. Eiximenis took on Saint Augustine's ideas and tried to materialize them into urban planning norms, so the earthy and the heavenly cities would be connected. He took up different sources and influences, both Christian and pagan but, as far as the final layout of the city is concerned, his ideas were quite similar to the ones put forth by the Roman architect and planner Vitruvius 19 centuries before ( Figure 6).   Context: the conformation of Hispanic port cities. Cartagena de Indias as an example In the sixteenth century, America's first wave of colonization takes place: across the New World, a frenzied activity of foundations progressed, with almost 300 foundations in that century. Cities became the cornerstone of Castile's colonial process: as Bronner puts it, 'the city was Spain in America' 20 in terms of government and administration. This is especially so in the case of fortified port cities, as Scarpaci underscores: 'Spain's geography of conquest and empire relied squarely upon forts and ports'. 21 However, we must remember the ultimate goal of a foundation in the Americas: whatever the constraints of place and circumstance, a town founding was a liturgical act sanctifying newly appropriated land. More than a mere exercise in cartography, urban design was the vehicle for a transplanted social, political, and economic order and exemplified the 'mystical body' that was central to Iberian political thought. 22 In view of this context, it seems puzzling that not until 1573 King Philip II dictates the first laws on the subject of urban development in the new territories, known as the Ordinances for the Discovery, New Settlement, and Pacification of the Indiesor 'Laws of the Indies' in their short form. 23 Therein, the square pattern is the accepted conformation, with a central main plaza containing  20 Bronner, "Urban Society". 21 Scarpaci, "Forts and Ports". 22 Morse, "The urban development". 23 Heineberg, "Desarrollo y estructura"; Morley, "Manila". the Cathedral and the Governor's building as symbols of power (see Rojas 24 for a deeper explanation of the plaza's symbology). The residences of the economic elite rose up around them and further afield were the areas to be occupied by the natives or the less favoured, in a premonitory division between 'centre' and 'suburbs.' Some authors like Nicolini remark that the rules of 1573 were belated as they favoured Baroque urbanism, rather than Renaissance urban planning, where the latter was much more convenient for the young American cities. 25 They point to previous rules, notably the ones dictated by King Charles in 1523 and 1524 26 as early norms for setting up cities in the Americas. These rules are some of the first of their kind, given the fact that in 1501 King Ferdinand gave complete planning freedom to Nicolás de Ovando, the founder of Santo Domingo (the first European-founded city in the Americas and today's capital city of the Dominican Republic). Clearly, by the beginning of the sixteenth century, the Crown had not outlined any urban planning strategies for the colonies. Some authors, therefore, see the 1573 rules as a compilation of what Castile had learnt and found fit, rather than a set of actual instructions. 27 As part of this 'learning process' reported by the extant literature, in the first decades of the colonial process, dozens of settlements were abandoned several years or decades after their foundation, for example, Santa María del Darién (Colombia), Nombre de Dios (Panama), etc. Others were moved to nearby places, such as Caparra/San Juan (Puerto Rico) or Santo Domingo, which was moved to the other side of the river just a few years after its foundation. 28 This trial-and-error might point to unprepared military officials in urban matters or to risky and premature decisions about location. 29 A connected issue is the 'idealism' vs 'realism' in the foundation process. Some authors remark on the utopian aspect of this process as it combined the Renaissance ideas with the opening of a New World, resulting in a burst of energy. 30 While this might have been possible in the very first decades of the conquest, it is clear that the growing number of urban norms and the security issues (see below) soon did away with utopian visions in favour of 'rule and order'.
Cartagena de Indias was founded in this context in 1533 (Figures 7 and 8).
Cartagena's new settlers had to face several challenges, apart from the natives' recurrent attacks, since the marshes and mangrove forests were a source of illnesses. However, the main difficulties were finding a fresh water supply and land to cultivate, and this made the founders doubt the location, until finally the place's strategic assets convinced them: an area made up of islets with lagoons connecting them is easy to defend, even with a limited number of military forces. Also, the area had a natural harbour thanks to its protected bay and deep waters. 31 In fact, the circumstances of Cartagena's foundation even contradict the settlement rules by King Charles about how a town in the New World had to be founded. According to these, there had to be enough water, available building materials, fertile lands around it to raise livestock, sufficient indigenous work power, etc. and none of these was the case in Cartagena. Urban planning therefore gave way to geostrategic and military considerations in the case of the foundation of this city. We contend that this circumstance, i.e. the prevalence of military strategies over other criteria to develop places, lasted throughout the colonial era. 24 Rojas, "La plaza". 25 Nicolini, "La ciudad". 26 "Ordenanzas de buen gobierno". 27 Hardoy, "El proceso"; Wyrobisz, "La ordenanza". 28 Socolov and Johnson, "Urbanization in Colonial". 29 Musset, "Abandonos", gives a general account of these issues across the Caribbean and New Spain 30 Lucena, "A los cuatro". 31 Borrego, Vázquez, and Muriel, "La trayectoria".
In the 1573 rules, the bad experiences of almost a century of coastal town development are evident. The troubles many Caribbean harbour towns had in their beginnings weighed heavily as revealed by the following excerpt: 'No more foundations will take place on the coastline, as these places are dangerous because of corsairs, because they are unhealthy environments and because the Indians there don't know how to properly cultivate the land'. 32 As for Cartagena, and many other Caribbean towns, they fully complied with ordenanza No. 37 as it states that port towns must be 'easily accessible by sea and by land, with good roads and navigation routes, so that one can easily enter or leave them, and carry out there the functions of trade and government and defence'. 33 The existing port towns were kept as essential places for defence and trade, and both functions are named in the 1573 rules, but none seems superior to the other. Cartagena's development was to follow the approved pattern for the Hispanic cities in the New World. However, the literature points to the differences, sometimes very obvious, between the ideas set forth above and what was carried out on the ground. The debate about the final layout of the colonial cities, from an almost canonical one in Puebla (Mexico) or Lima (Peru), to more unorthodox layouts like Cartagena's, where the main square is secondary to the port's plaza, shows a process of learning and adaptation by the colonial planners (Figures 9 and 10).
In the end, the basic, ideal urban pattern would be adapted to the topography of the territory, in a trade-off that is found in many places.
Rather than perfect square blocks, in many Hispanic cities we can find different sized rectangular blocks and even angled streets. One question to consider is 'how much variation' Figure 7. Oldest known map of Cartagena from around 1570. Source: Archivo Cartográfico de la Real Academia de la Historia, 9 / 4856, folio 126 r°. 32 Morales, "Teoría". 33 "Ordenanzas de poblamiento", no. 37.
was allowed, and this is clarified by a comparison with Brazil. Durán 34 parallels Barichara (Colombia) and Ouro Preto (Brazil), two inland towns with similar functions and comparable topographical conditions. She underscores that the grid prevailed in the former and a spontaneous layout more adapted to the environment is to be found in the latter, so Castile stuck more to the grid than other countries.
In this context, it is worth pointing to the specific debate about colonial port cities that assigns the port's plaza as a central space within the city. Solano sums this up as follows: the main difference with the port square and the main square is that, the latter was built top-down and under control of the church, the authorities and the economic elites. The port's plaza was built alternatively, i.e. bottom-up, by different concurrent forces. This meant the main square only retained the function of representing power. 35 Borrego et al. (2009) 36 also assert that, in colonial port cities, the urban grid would be developed from the port to facilitate things for the shipping traffic. According to these authors, this explains why such places show a much more variegated layout than their inland counterparts. They even go as far as depicting Cartagena as a multi-polar city consisting of several connected plazas. In sum, colonial port cities displayed two (or several) poles, each with its own dynamics and purposes.
Some researchers insist that there were few variations in the urban grid, even taking into account different urban functions such as mining towns, port towns, etc. Moreover, by the 1520s, the final layout of the cities was decided and from then on, the basic grid model was replicated across  34 Durán, "La malla". 35 Solano, "Trabajadores". 36 Borrego, Vázquez, and Muriel, "La trayectoria".
colonial America. The permanence of this urban layout may also be because Baroque urban planning and architecture never got a foothold in America. This meant the Renaissance model remained as the only urban model throughout three centuries; a simple (not to say 'monotonous') and standardizing model, and yet at the same time, practical and replicable on a large scale, therefore convenient to the new territories. 37 The trade function of Hispanic colonial port cities The Hispanic colonial cities were also conceived as strong connectors between Castile and the newly conquered territories. In the words of Schneier: 'from Mexico City […] to Buenos Aires, a network was set up whose main function was ensuring the control of the lands as well as maintaining connections with the metropolis'. 38 So, each colonial city was also a trade and transportation node. Specifically, the group of ports connecting Castile with America came to be known as Carrera de Indias [The course of the (West) Indies], served by a flotilla of traveling merchant ships protected by several war ships, in a round trip that was organised twice a year, in the spring and fall. Cartagena became one of the main ports in the Carrera, and the reshipping port for the noble minerals extracted from the mines in Peru, which were transported via the ports in Lima and Portobelo, after crossing the Central American isthmus. 39 All this activity meant the Caribbean became a world trade hub, a condition that would soon attract pirates, see Figure 11.
The arrival of a convoy of ships was a major source of activity in the affected ports bringing news, people and goods, and therefore prompting a temporary trade fair (see also further below). Some authors remark on the buzz and frenzy of Cartagena, Veracruz and Portobelo when the flotilla was there, contrary to the idle times when the ships were away. This sea route, consisting of a group of ports of call nicknamed 'The Gates to the Indies', was in place for some three centuries, until the  37 Nicolini, "La ciudad". 38 Schneier, "América Latina". Other authors have put forth the vision of the Carrera as trade route. 39 Stangl, "The land mail".
independence of the American territories in the early nineteenth century. 40 The importance of these trade routes and trade fairs, which were part of the big driving force in the colonial process, is undeniable (see a complete map of the connected ports and the products forwarded on the Carrera in Supplemental Materials, Figure B).
The military function of Hispanic American cities: building fortified cities in a war-plagued Caribbean Alongside the trade function, the colonial cities also fulfilled an obvious military function: occupying and maintaining the territories was one of their essential functions, as they were the points from which the authorities exerted their power over large areas. The menaces posed by corsairs and the European powers rivalling Castile transformed them into true fortresses: for over two centuries, huge sums were invested in one single goal, i.e. making them completely unassailable.

Wars, pirates and the need for protection
Cartagena fell prey very early to treasure-seekers and rival armies, notably the English and French. 41 The invaders would take the city and its treasures and ask for ransoms to leave it and to free the captive population and their religious and civil authorities. The nascent town in the sixteenth century saw no less than four invasions, two by the French corsairs Robert Baal (1544) and Martin Côte (1559) and another two by the English pirates John Hawkins (1568) and Francis Drake in 1585-86. The latter siege is considered the most harmful in that century, as Drake commanded a flotilla of 23 ships and left behind a destroyed and demoralized town 42 (Figure 11): In the seventeenth, and especially in the eighteenth centuries, the Caribbean became one of the first spaces in man's history where proxy wars were fought by far-distant powers. In this context, the two worse attacks Cartagena suffered were in 1697 by the Frenchman Baron de Pointis, whose destruction trail was followed by the pirate Ducassé one year later, and had the military architects doubting the robustness of the defence structures. However, both in the local historiography and popular memories, the most brutal attack the city endured happened in 1741, led by the English admiral Edward Vernon. 43 He put the city under siege for several months and was even able to capture some of the surrounding fortresses, but in the end, he had to pull back with no success. The English brought an army of 186 ships in quite a unique display of power. The city walls and San Felipe's Castle (by then a smaller fort called San Lázaro), as well as the preparedness of the residents, played a crucial role in repelling the English attack (see also next section).
Cartagena was by no means the only colonial Hispanic port under recurrent attacks: the armies or the pirates would also seek other Caribbean ports along the Carrera de Indias route, which suffered similar fates as they faced the same invaders as Cartagena. Hawkins and Drake would even go as far as associating in 1595 to attack San Juan. It was therefore clear from the outset that, if these towns were to survive and prosper, a consequent set of defences had to be built in each one. That is why the Crown endowed first-tier Caribbean cities (Cartagena, Havana, Veracruz) and second-tier towns (San Juan, Campeche, etc.) with walls and fortresses that were upgraded and developed over almost three centuries. In the specific case of Cartagena, Kagan wrote that 'it erected 40 Chaunu, et al. "Sevilla y América". 41 Galindo and Peñalver, "Rehabilitation techniques"; Aparicio, "Mar de sangre"; Membrillo, "La batalla". 42 Lemaitre, "Breve historia". 43 For an account of this event, especially the meagre means the Spanish could count on, see Serrano, "El éxito".
what was surely among the most impressive arrays of artillery platforms, fortresses and walls ever constructed in the New World'. 44

Building for protection: walls, fortresses and castles
The construction, reconstruction and modification of these structures took almost the whole of the colonial era, and profoundly marked not only the urban landscapes of the Hispanic Caribbean port cities but also their economy and society. In Cartagena, this intensive-manpower labour was provided by slaves, convicts and the mix-raced. 45 In parallel to that, imported troops from Castile or other territories in the Americas provided external security to the city and internal security to the port. 46 It is worth noticing that city walls were not built everywhere: such expensive projects only made sense at the Empire's borders, such as the Caribbean and, later on, in South America: Lima and Trujillo (Peru), Buenos Aires, Montevideo, etc (See Supplemental Materials, Table B). Crucially, no inland cities or towns were walled. The process of setting up defences, like choosing the cities' locations reported further above, was quite erratic. 47 Some authors state that, in the first decades of colonization, in many coastal settlements, the mendicant Orders (which were for open and spiritual places) convinced the authorities not to build walls, yet this matter was quickly reversed after the first pirate invasions. As surprising as it may seem, for most of the sixteenth century, the Caribbean Figure 11. A drawing from the sixteenth century depicting Drake's flotilla attacking Cartagena in 1585. 44 Kagan, "Urban Image". 45 Porto, "Fortalezas"; Vázquez, "Mediohombre". 46 Espinosa, "La tejedora". 47 Kagan, "Un mundo". towns remained without walls and were quite badly defended. 48 The literature repeatedly underscores the inappropriate defence planning and the fragility of the wooden palisades, like the land wall in Santo Domingo, which Drake overcame easily in 1585. Cartagena shyly put up its first defences (some canons and platforms) only in the 1570s. However, as the decision was taken to make the fortified structures the main means for resisting invaders (instead of meeting them at open sea with squads of war ships), fortresses, bulwarks and walls became constitutive elements in the places that displayed them, and they evolved into important urban and symbolic structures. The unwillingness to fortify towns for most of the sixteenth century resulted in yet further uncertainty regarding their development, similar to that stated above about the locations in the first decades of colonization.
In the years following the foundation, Cartagena's settlers protected themselves from the natives' attacks with forts made of large wooden pieces intertwined with canes. The openings in these rudimentary walls would be covered with a mixture of clay and small stones. These handcrafted structures soon gave way to walls made of rounded stones and mortar, as the enemies were no longer the natives (decimated by the illnesses brought over from Europe), but the corsairs. Inner city corridors were designed to quickly shift canons and troops. 49 In the aftermath of Drake's attacks, the Crown took the decision to implement the defences' model used in Italian cities. The King hired Italian engineer Battista Antonelli who, together with Juan de Texeda, built a range of fortifications across the Caribbean. The Italian fortresses in the sixteenth century consisted of a set of buildings, each guarding a strategic point, with interconnections forming a network of points for mutual support. In Cartagena, these ideas gave rise to forts like Boquerón on Manga Island, as well as the defence bulwarks along Bocagrande and Bocachica, interconnected by wall sections. The ability to cross-fire end to end was guaranteed, and there were some extra supports in the form of mine fields, chain blockades between the different forts and improved gun precision from the outermost bulwarks on the islands (Figures 12 and 13). 50 A second moment for the military-built structures came after De Pointis' attack in 1697. This attack showed that the Caribbean fortresses had become obsolete and weak and needed an upgrade. 51 The main weakness in the defence system was its inability to confront an enemy attacking the city from different points. The modifications aimed at improving the connection between the fortresses via several tunnels, labyrinths and shafts, which would allow for better reciprocal backup among the different sections in the event of an attack. To this end, the fortresses' walls were reinforced with a combination of bricks, stones and mortar, and they were partly repositioned. The wall layout also changed, becoming more compressed and enclosing the fortresses in a more precise way. 52 After Vernon's attack in the mid-eighteenth century, another upgrade was badly needed. In the first years after the attack, much attention was paid to enlarging the highly-strategic fortress of San Lázaro, which became San Felipe's Castle, a reconstruction led by Juan de Herrera. However, the remaining fortresses were left unattended. Before the tensions with England escalated in the last two decades of the eighteenth century, viceroy Guirior asked the Crown to renovate the entire system of fortifications in Cartagena, as the system: 'had to enclose the city with well-aligned, robust walls and well-built bulwarks, including the necessary artillery and troops.' 53 48 Kubler, "Mexican Architecture". 49 Galindo, "La construcción". 50 Galindo, "La construcción". 51 Lemaitre, "Breve historia". 52 Galindo, "La construcción". 53 Guirior, "Instrucción que deja".
For this final fortress upgrade in 1772-75, the French and Flemish fortress models were transferred to the colonial cities in the Caribbean, under the supervision of the military engineer Antonio de Arévalo. This type of fortresses favoured the combination of stretches of shorter walls with large bulwarks, so as to create bays for shooting the invaders from above. The soils were analysed (for the first time in the city's history) to get more solid basements. Novel formwork techniques made inclined walls possible and the wall thickness was increased to resist the impacts of cannon bullets. Overall, the masonry works topping the structures made for longer building times and higher costs -King Charles III is said to have repeatedly bemoaned the exorbitant building costs of Cartagena and Havana. In the end, however, these more complex and heavy structures guaranteed greater resistance against the impacts of artillery. Two outstanding examples of this architecture in Cartagena are San Fernando's Castle and San Felipe's Castle. The latter, in its former version as a humble fortress, was instrumental in repelling Vernon's attack and provided an important connection for bulwarks and forts, apart from protecting the neighbourhoods on the islands outside the walled city. Last but not least, another major work from this era was the breakwater at Bocagrande, a strategic and innovative project. One aspect to question here is how Arévalo dealt with the layers of fortifications from different eras. A worthy response is that pragmatism and cost efficiency led the decisions in Cartagena andwe may inferother Hispanic Caribbean cities: 'The concern and interest in preserving the existing constructions when undergoing repair works stand out particularly, not from a conservationist point of view, but encouraged by saving on expenses and the rational handling of the construction materials.' 54 It is considered that, with Arévalo's works (who died in Cartagena in 1800), the city's military buildings, including the city walls, were finally completed after more than two centuries of building and re-building, thus attaining the so-longed for 'unassailability status'.
The pre-eminence of defence matters in urban planning projects is also upheld in the eighteenth century, so it seems to be a continuous trend since the city's foundation (see further above) throughout the colonial period. As Marchena explains for eighteenth century Cartagena: Some housing blocks close to the walls were demolished so as to avoid the houses leaning on the walls. Several new squares were opened and some angles in existing housing blocks were modified. In sum, the city's landscape was intervened upon and, by analysing existing documents regarding this American city, it seems obvious that most modifications had a military ground not an urban one. 55 Furthermore, it has been pointed out above that the colonial towns displayed a 'learning process' as far as their urban plans are concerned, following the rules or deviating from them as required by the conditions on the ground. At the end of the present section, another learning process regarding the defence structures is to be highlighted: the constant improvement to the walls and fortresses, following different building patterns and styles (first the Italian model, then the French-Flemish one), which shows an ongoing-learning ability over the centuries (Figures 14 and 15). So, in the case of Hispanic colonial cities, there was no 'preferred' defence building style, but there was a continued progression always striving for better defence structures, with a pragmatic approach to get the 'best results at the cheapest price'. Speaking of 'price', the next subsections delve into the financial facts that made the defences possible. 54 Galindo and Peñalver, "Rehabilitation techniques". 55 Marchena, "El poder".
On the Spanish Empire's financial capacity for building military infrastructure The first point to highlight is that the Hispanic colonial port cities had a financial double function: they were the places where the taxes and noble metals were gathered and shipped to the metropolis and, at the same time, the royal situado 56 was invested in their defence infrastructure. 57 The taxes levied from the American territories increased in the eighteenth century as the House of Bourbon started reining in Spain. Clearly, in order to upkeep the Empire's financial status, it was crucial that the taxes and noble metals transiting form America to Spain were well-protected, and so the Crown was forced to invest in maintaining and extending the fortified port cities, as well as in the different bodies of officials who kept them functioning, including the armed forces. 58 The war ships protecting the Carrera as well as other war ships in the Caribbean were funded by the taxes collected in the colonies. 59 Figure 12. and 13. Evolution of Cartagena's outer defences from the sixteenth (left) to the eighteenth century (right) with the changing access to the port (Source: De Pombo, 1999 83 ). 56 Royal 'Situado' was a tax levied from several viceroyalties which was entirely reinvested in building up and upkeeping fortresses. 57 Wasserman, "Real Situado"; Dubet and Solbes, "El rey". 58 Torres, "War". 59 Greifensteiner, "Situado".
As a matter of fact, the Royal Treasury prioritized the payment of expenses related to past wars and the royal family's excesses. These two, together with the costs of the growing colonial bureaucracy and the need for public works across the colonies, prompted a lower investment in military infrastructures in the fortified cities in the Americas. Therefore, their expansion came to a halt.
By the mid-eighteenth century, as the tensions with England heightened, the Caribbean cities were in need of investments to strengthen their military-built structures. As the financing was short because of the aforementioned reasons, soon every merchant guild in every colonial city would be called upon to fund these works, see further below.
Trade vs military: managing and financing the port city's defences 60 The viceroys' reports from eighteenth-century Cartagena give unique insights into the intricate relationship between the local trade industry and the city's military, as well as its spatial and urban consequences. Thus, they contribute a response to the question about Cartagena's military function versus its trade function. As said before, the city would come alive with the arrival of the ships from the Carrera de Indias, taking noble metals from the Americas to Spain and bringing back all types of manufactured goods that could not be found in the Americas. This would give rise to a fair trade in each port in the Caribbean that the ships called upon. The merchandises not traded followed their route further down to the following ports in the Carrera, and for Cartagena these were Portobelo, Panama City and Lima. Examples of goods that travelled further were flour or most textiles, which could rot quite quickly under Caribbean weather conditions.
Such close circuits and monopolistic conditions, and the insignificant manufacturing industry in the colonies, created the perfect dependency scenario and also an ideal scenario for the emergence of smuggling in response to this situation. 61 In fact, during the eighteenth century, laws were passed giving broad powers to the viceroys all over Hispanic America to fight smuggling in their territories. The reason is obvious: traders selling smuggled goods were able to undercut prices by some 30%, ruining legal traders and, most importantly, underfunding public works as fewer taxes could be levied. 62 The Crown displayed a host of actions to counter smuggling, such as strict customs controls on incoming and outgoing goods, setting up a register of ships, building transit warehouses in the smaller transit ports on the rivers to check on the merchandises, etc. Trespassers in New Granada (be they smugglers or cooperating officers) were punished with imprisonment in the fort of San Sebastian in Cartagena. 63 One of the first urban impacts of these actions may be found in Cartagena where they built the customs house and warehouses beside the port wall. This allowed officials to keep a permanent eye on the goods entering the city or transiting towards other ports in America. The effects of these actions were soon felt: between 1740 and 1750, merchandise was seized worth seven and a half million pesos.
that, without a developed class of traders, the local supply of basic goods could not be guaranteed in times of peace, nor the loyalty of the trade guild in times of war and besiegementwhen the merchants would take over the supply and logistics functions any army requires. Besides, the merchants and their servants, alongside the city's craftsmen, served as volunteers in the army in times of war. 64 As such, they had to be ready to respond to any eventuality, for instance when it came to repelling the English besiegement in 1741. As this attack was announced well ahead, everyone in the city cooperated in reinforcing the weakest points of the precinct walls under the direction of the local military engineers. This was decisive in preventing Cartagena from being taken by the English, and shows that the trader guild's contribution to the city's status was crucial. 65 The merchants had to gamble with their accumulated wealth in war times in order to carry on with their businesses once hostilities ceased. They did so by extending credits most of the time, though sometimes part of their estate would be confiscated straight away or the funding required would be forcefully levied from them, according to each one's estimated economic status. 66 Thus, in this context, a well-kept city with its built defences in good condition came to be regarded as a loyal place inhabited by honest, law-abiding residents. Apart from the local tax revenue, the state's funding would also contribute to building its defences (though with funding cuts as the century progressed, see further above). So, in the course of the eighteenth century, several colonial port cities in the Caribbean became virtually unassailable.
In the case of Cartagena, the joint investments by residents and public authorities in the castles and fortresses had another benefit in the realm of public order as, in the eighteenth century, some of these were turned into prisons, and very harsh ones at that. These would provide cheap labour as the prisoners were forced to help with the upkeep of the built defences.
Having large penitentiary facilities in the city justified the presence of a high number of troops to guard the prisoners. In fact, for general attorney Moreno, the difficulties in financing Cartagena were not related to the upkeep and enlargement of its military precinct, but rather to the salaries of the troops, civil servants, justice administrators, etc. without whom the city would not be able to function. Religion, military and bureaucracy were the main means for controlling the town's economic and political life, and therefore countering any threats inner enemies may pose, these becoming much more of a real danger in the latter years of the eighteenth century. 67 The viceroys' reports from that era give first-hand clues on the evolution and financing of the defence structures in Cartagena. For the 1740s, the report by viceroy Eslava, goes into detail about updating the fortresses after the attack in 1741. By 1760, viceroy Solís reports on the financial difficulties in closing the area of Bocagrande (which finally would be done by creating a breakwater, see above). Later in the century, viceroy Guirior points to the fact that, although a huge economic effort had been made to upkeep the whole military precinct, some parts of it were still quite vulnerable. 68 This report, written in a lobbying tone, is what finally prompted Spain to send engineer Antonio de Arévalo, who really made the city unassailable (see previous section).
Every time new works started and a new round of funding was required, the above-explained tensions would spark up between officials and merchants. Thus, this era was marked by an uneasy side-by-side between the military and the merchants' guild. It was a situation of mutual interdependence, a tit-for-tat scenario. Having the port cities well-fortified, however, was a matter of general interest to safeguard Spain's military and political position in the Americas and, on a smaller scale, it was also crucial for the merchants to carry on with their trade. 69 This may also be seen as a 'virtuous circle': the better protected a city was, the more revenue for the merchants and consequently the more taxes for the officials to invest in the defence structures to make the place even safer. While one can discuss to what extent each of these two groups were dominant from a social or economic point of view, it seems clear that, when it comes to urban planning, the military layout prevailed. A solid system of defence forts and walls was erected on the ground (as well as their upkeep and financing) and a street grid and blocks inside them, best suited to defence purposes. Notice also that the tensions described in this section were common across the Empire, as Del Valle 70 reports for Mexico City's merchants, so Cartagena was by no means a special case.

Discussion and conclusions
The major goal of this paper was to shed some light onto the form and function(s) of Caribbean colonial port cities. Overwhelming evidence has been brought about supporting the idea of military pre-eminence in Cartagena's case, evidence which might be transferred to other Hispanic Caribbean port cities as well. 71 According to a local historian, 'Cartagena was born as a military place, and this is its most distinguishable trait. Militias, regular troops and military engineers were there since its inception. Defence considerations weighed most when its location was chosen'. 72 Another local historian goes as far as asserting that it was the military function, which permanently changed the city's landscape, ultimately explaining Cartagena's not-so-regular plan. 73 Urban development choices were also guided by defence considerations, going so far as having the coastlines changed on military grounds. 74 This was the case in all fortified Caribbean cities as well: they were the first frontier of the conquest, and subsequently they found themselves facing a sea turned into a battleground, so it is obvious that the military function was to be the most important one in themso the line of thought of many authors. As the inland plantation or mining towns were not so exposed to danger, they were probably better suited to becoming places with economic or cultural pre-eminences.
However, besides these strong military arguments, it is worth underscoring that the trade function keeps coming up as an important historic role of these cities, such as in a report to the King from the mid-seventeenth century, which devotes its bulk to military questions but does not forget the trade importance of Cartagena. 75 In the end, we have to acknowledge that this is not a disjunctive, but rather we are looking at two ever-present and interdependent functions, whose importance shifted in the course of colonial history depending on the circumstances. This juxtaposition of functions has also been posited in recent years by the historiography.
As for the questions about the colonial city grid in the Americas, it came from the European grids and was evolved and perfected in America. 76 The grid emerged as an evolution from late medieval concepts and developments (the literature review above lists some less-researched ideas in this respect) and from Hispanic America it kept evolving, as in North America in the nineteenth century, thus displaying high adaptation capabilities to different urban purposes and new latitudes, and 70 Del Valle, "Donativos". 71 For the idea of the military pre-eminence in San Juan, see Pabón-Charneco, "San Juan". 72 Segovia, "Las fortificaciones". 73 De Pombo, "Trazados urbanos". 74 Gómez and Carvajal, "Fortificaciones". 75 Guerra, "Relación". 76 Brewer-Carías, "El modelo". making for 'pragmatic' urbanism. 77 However, we must not forget that there were also different place designs in the continent, for instance the cities of Guanajuato (Mexico) and Asuncion (Paraguay), important places in their respective geographical contexts, which grew in an organic fashion (see Table B in Supplemental Materials). In the seventeenth century, the Renaissance-built towns would live a Baroque life becoming 'Baroque social urban landscapes', so even socially speaking, the grid is a flexible structure: 'the cities were controlled but not unreceptive to new trends'. 78 In this respect, we would like to quote Guidoni and Marino, who opened the door to social and critical frameworks back in the 1980s (a research avenue which has grown since, with the potential to overcome so much form-obsessed empiricism). According to these authors, 'The categories of "Classical" or "Baroque" do not fit into those political, economic or social phenomena which ultimately condition the urban projects and the urban selection processes.' 79 A final, important finding has to do with the contrast in the urban grid's rigidity versus the flexibility of the defence structures in the Caribbean port cities. In fact, while the urban grid, and even the cities' architecture, remained unchanged throughout the colonial era, the walls and fortresses were modified several times according to the set strategies. This also meant switching the fortresses building style when necessary: from the Italian to the French-Flemish stylewhile the cities would forever stick to their Renaissance style. True that they grew inside the precinct walls, but only in terms of densification, and this was a quantitative not a qualitative process. So, the final picture is an outer precinct evolving to catch up with the newest defence techniques, with an inner city caught in its primigenial urban and architectural forms. Some authors have given a 'strategy' explanation for that: the more military importance a city had, the slower it would evolve in urban terms. The perfect example to backup this explanation is nineteenth-century San Juan, where the Spanish military stubbornly opposed demolishing the walls and any other urban developments, against the citizens' will. 80 While not dismissing this line of reasoning, we would like to propose a complementary explanation: the Hispanic Caribbean cities experienced high socio-political dichotomies, be they external (war/peace) or internal (military/trade, the privileged/the excluded). Since their beginnings, traders strived to make them open places for business and the military pushed for shut places for reasons of defence, a dichotomy resulting in a shifting perimeter versus an immutable core on the ground. Add to this their background of unstable origins and some 'learning processes' we have mentioned and is to expect that, amidst their volatile and risky world, the inhabitants must have derived a sense of stability and belonging from their urban grids and cores. Therefore, and perhaps subconsciously, residents were content with a permanent, unchanging urban landscape, and the urban core and the grid provided exactly that. This contrast between the outer precinct walls and the inner-city streets can be felt even nowadays in Cartagena and other Caribbean fortified cities. 81 This vision of the city as a single unit possessing shifting and immutable parts unifies the different layers of urban history we have encountered by providing a novel framework based on semiotics, which is to be further researched in the future. 82