Style: Notes on the Transformation of a Concept

Style has been a key concept in architectural discourse since the 18th century, yet its meaning is far from unequivocal. This essay traces the shifting meanings attributed to style in German architectural thinking from the mid-18th to the early 19th century. Reading and discussing texts by J.J. Winckelmann, J.W. Goethe, C.C. Hirschfeld, A.W. Schlegel, H. Hübsch, and F. Eisenlohr, I study the multifarious uses to which style was put in this period and look at the effects these uses had on architecture.

One scholar who has studied the expansion of the concept of style in the 18th century is Caroline van Eck, an authority on the influence of classical rhetoric on architectural thinking in the modern period. Eck shows how French architects such as Germain Boffrand and Jacques-Franҫois Blondel systematically applied rhetorical concepts in their theoretical works, and how the concept of style became a linchpin for new theories of architectural expression. She quotes Boffrand from his 1745 Livre d'architecture: Through its composition a building expresses, as if in the theatre, that the scene is pastoral or tragic; that this is a temple or a palace….
[A]ll … buildings must proclaim their purpose to the beholder. If they fail to do so, they offend against expression and are not what they ought to be. The same is true of poetry: this, too, has its different genres; and the style of one does not suit another. (Eck 2002: xxii) Style, here, is closely linked to genre, describing architecture's expressive potential. Blondel used the two terms more or less synonymously, defining style in architecture as 'the true genre which one must choose with respect to the motive which led to the construction of the building' (Eck 2002: xxv). Seeing style as 'the poetry of architecture', Blondel's and Boffrand's architectural thinking was closely patterned on the rhetorical tradition by which the speaker/architect has certain modes of expression at his or her disposal. Style is seen as a matter of choice from within a predefined range of possibilities; a choice which in its turn is governed by decorum.
This gradual expansion in the use of style from the domain of language to that of art and architecture can be found in the German sphere, too, although the process took a little longer. Christian Ludwig Stieglitz did not include an entry on style in his Encyklopädie der bürgerlichen Baukunst (1792), preferring -like Immanuel Kant in the Critique of Judgement published two years earlierto speak of taste and character. The philosopher Johann Georg Sultzer, on the other hand, used style frequently in his two-volume Allgemeine Theorie der schönen Künste (1771-74), a work organized as a dictionary with alphabetically ordered entries. Expanding the rhetorical notion of style, Sultzer compared the genres of speech with different styles of painting: Just like the art of speaking, painting adopts soon the elevated, passionate tone, soon the tone of ordinary everyday life, or it stays in the middle between the heroic and the quite ordinary. Hence arises in painting, as in speech, a threefold style. (Sultzer 1771: I, 451) 3 Sultzer's loyalty to the rhetorical tradition shows itself not least in the double entry 'Schreibart; Styl', where he defined the two terms jointly: 'The particular mark imprinted onto the work by the character and the mindset of the artist seems to be what one counts as the manner of writing, or the style' (1774: II, 1047). 4 Although Sultzer and his French contemporaries applied the concept of style to art forms such as painting and architecture, their use remained closely aligned with the rhetorical tradition. This was changing rapidly, however. From being a heterogeneous but seemingly uncontroversial concept taken from classical rhetoric, style was propelled to the centre of late 18th-century aesthetic debate and attributed widely different meanings. In the Germanspeaking context, it seems to be appropriated by three different fractions. Firstly, it would become the operative concept in an entirely new form of art history, inaugurated by Johann Joachim Winckelmann. Secondly, promoters of a new sensationalist aesthetics would make style a vehicle for thinking about the emotional effect of art and architecture, a development I will illustrate by the work of the garden theorist Christian Caius Hirschfeld. And thirdly, style would be used to coin a principle of perfection in art; a measure, as Goethe put it, of art's 'highest achievement ' (2016: 876). These three connotations would transform the concept of style radically, opening it to new interpretations and furious debates in the coming centuries.

Style as a Historiographical Index: J.J. Winckelmann
The preface to Johann Joachim Winckelmann's History of the Art of Antiquity (1764) reveals how central the concept of style was to his new art history: 'The history of art', he announced, 'should inform us about the origin, growth, change, and fall of art, together with the various styles [Stile] of peoples, periods, and artists ' (2006: 71). Style was a vehicle to analyse both these issues, allowing Winckelmann, on the one hand, to measure cultural development (identifying early, high, and late style within any particular culture) and on the other, to identify and differentiate cultural epochs, speaking of Egyptian style, Etruscan style, Greek style, etc. Style became not only a way to grasp the particular character of a culture's artistic output but also an analytical tool to explain why it had turned out the way it had.
The title of Winckelmann's first chapter, 'Origin of Art and Reasons for Its Diversity among Peoples', bears out this twofold ambition. Winckelmann outlined two types of causes for this diversity: 'internal' causes such as climate and topography, and ' external' causes such as customs, religion, and political structure. The two were not unrelated. As Winckelmann saw it, climate and natural conditions had profound effects on culture on all levels, determining both the human physiognomy and the human way of thinking and making. And because ideals of beauty derive from actual observations of the human body, climate can be said to influence even our sense of the ideal (2006: 118). It was this line of reasoning that made Winckelmann propose that mild climes produce more beautiful people, and beautiful people produce greater art, because they have better models to imitate: In judging the natural talent of peoples … we must therefore take into account not merely the influence of climate but also education and government. For external circumstances affect us no less than the air that surrounds us, and custom has so much power over us that it even shapes the body and the senses instilled in us by nature in a particular way. (2006: 121) It is the artistic outcome of these circumstances -external and internal -that Winckelmann called style. He pursued the topic systematically, organizing each chapter first with a mapping of the circumstances shaping a given culture, then a description of the resulting style and its development over time. Style, then, is a result of particular conditions, and when these conditions change, so does style. By carefully analysing the external and internal factors influencing different peoples and periods, Winckelmann tried to identify the 'probable cause for the nature of their art ' (2006: 159). The particular conditions that shape the bodies and souls of a people, he implied, correspond to an artistic expression unique to this people alone, i.e., their style. Such expression changes with time and circumstance, testifying both to the unique character of a specific culture and to the lawful development of history as such.
Winckelmann's insistence on natural and historical circumstances as the precondition of art and architecture introduced a new relativism into aesthetic judgment. Winckelmann himself did not tackle this head on; in fact, he steadfastly defended the perfection of Greek art and considered the Greek high style an ideal with universal validity. Yet by presenting style as the outcome of natural and cultural conditions and implying that each civilization has its own aesthetic standard, he anticipated a radically historicized understanding of style (Piel 1963;Hvattum 2017). Rather than referring to a shared store of expressive possibilities as in the rhetorical tradition, style came to be seen as the unique fingerprint of a particular historical epoch, an obedient servant of the zeitgeist, as it were. For Winckelmann, writes the German art historian Lorenz Dittmann, 'Style is nothing but the historical unfolding of beauty ' (1991: 216). 5 Winckelmann may have been the first to use style as a systematic, historiographical tool, but the idea that particular periods display particular styles was not without precedent. Ten years before History of the Art of Antiquity, Zedler's Universal-Lexicon addressed style in music: STYLUS, Italian Stilo, French Stile, is understood in music as the art and manner in which each person in particular composes, performs, and expresses himself. All of this differs according to the genius of the author, the country, and the people, as well as the demands of the material, the place, the time, the subject, the expression, and so on. (Zedler 1731(Zedler -54: 40, 1469 The emphasis is still on style as a genre-related choice, but in addition, peoples, places, and historical periods are granted their own styles. A similar passage was added to the second edition of Encyclopaedia Britannica, where style in music was described as ' a peculiar manner of fingering, playing, or composing … which is very different both in respect of different geniuses, of countries, nations, and of the different matters, places, times, subjects, passions, expressions, &c.' (1783: X, 8319). Winckelmann, then, was not alone in expanding the meaning of the term from a consciously chosen mode of expression to a sort of expressive outcome brought about by particular circumstances, be they historical, geographical, or personal. In contrast to the rhetorical tradition, style, here, is no longer a choice, but a destiny: a measure of the correspondence between given circumstances and artistic expression.
Winckelmann's new notion of style as the relative outcome of certain historical conditions lent itself to two conceptual uses. Firstly, as an expression of the way art and architecture respond to the relative character of time and place, it allowed art and architectural history to be seen as a succession of epochs, each of which was the product of specific conditions manifested through a distinct architectural expression, or style. Secondly, as a condensed expression of a particular time or place, style could be seen to express not only the relative status of any given civilization but also its inner ethos; its unique, inimitable historicity. Style was the external expression of this individual, epochal unit, indexing a series of internal and external factors that contribute to making each historical moment different from any other. Both these possibilities would be explored in architectural thinking after Winckelmann.

Style and Atmosphere: C.C. Hirschfeld
Winckelmann's notion of style was very different from that of his French contemporaries. If Boffrand and Blondel concentrated on the expressive and emotive potentials of style, Winckelmann focused -at least seemingly -on the taxonomic. But sensationalist aesthetics was making its way into the German-speaking world too. An interesting example is the garden theorist Christian Caius Hirschfeld, whose wildly popular Theorie der Gartenkunst was published in various versions and in several volumes between 1775 and 1785. Oscillating between Stil and Styl (a common variation in German texts from this time, reflecting, perhaps, the contested etymology of the term), Hirschfeld used style to classify landscape scenes and garden buildings according to genre and expression. He described landscapes displaying an ' elevated style' (1780a: 91), wrote about views in a 'rural style' (1780a: 147), and observed temples in an ' antique style' (Hirschfeld 1780b: 67). Speaking about 'high', 'noble', or 'pure' style, Hirschfeld aligned himself with a well-established rhetorical tradition. Yet he also introduced stylistic characterizations that were uncommon at the time: On rough, rocky promontories by the seashore, or on high cliffs boldly stretching into the river, castles or towers in Gothic style are among the most appropriate buildings; their rawness, their strength, and the memory of their former use, all of this agrees very well with the wilderness of the place. (Hirschfeld 1782: 37) 7 The combination 'Gothic style' is interesting for several reasons. For one, it is very early. Georg Germann argues that the expression is used for the first time in German in August Böttiger's travel memoirs from Wörlitzer Park from 1797 (Germann 1974: 26), yet here we find it in Hirschfeld some fifteen years earlier. Secondly, Hirschfeld used the expression in a very particular way, not so much to characterize a historical period (in this case the Middle Ages) as to point to its potential impact on the present. Placed in the right context, he hinted, the rugged and primitive expression of Gothic architecture could exercise a profound emotional effect on the modern viewer. Gothic ruins and hermitages had a capacity to intensify the ambiance of particular kinds of landscapes; medieval chapels could 'touch the soul with their gravity and solemnity' when placed in the right setting (Hirschfeld 1780b: 97-108). As harbingers of distinct spiritual content, different historical styles evoke different atmospheres -Stimmungen in German -capable of transporting the viewer into different mental states: Thus the ruins of a mountain fortress, a monastery, or an old country estate all awaken very different emotions, each heightened by contemplating the era and other circumstances that in themselves can be so very diverse. One moves back into the past, for a few moments one lives again in the centuries of barbarism and feuding, but also of strength and courage, in the centuries of superstition but also of piety, in the centuries of savagery and lust for the hunt, but also of hospitality. (1780b: 111, 2001: 303) 8 History, represented by style, is for Hirschfeld a variegated pallet of expressions, capable of triggering emotions and associations. Each historical epoch has its unique atmosphere, he suggested, making historical styles effective means of heightening the emotional impact of a building or a garden. This is not an archaeological use, intended to impart knowledge of any particular historical epoch, but a use in which the historical content is sublimated to an aesthetic experience and operationalized into a project. Styles are not simply history lessons but attain ' a kind of universal citizenship, … accepted with pleasure everywhere, so that the sight of them transports us to a place where the imagination is enraptured by beautiful images' (1780b: 75, 2001: 287).
Hirschfeld's 'rapture' sounds very much like that of the young Goethe, whose epiphanic description of Strasbourg cathedral from 1772 is an early example of such protoromantic atmospherics. Yet Hirschfeld went considerably further. The atmosphere of past epochs, he argued, can be liberated from its particular historical significance and turned into an emotional trigger for the present, all by means of style. Through a knowing use of style, architecture can extract emotionally saturated images from history, ' clean' them of their particular historical content, and translate them into pure, affective form.
Hirschfeld's notion of style relates to the rhetorical tradition in which the choice of style aimed precisely at awakening emotions in the audience (see for instance Book 2 of Aristotle's Rhetoric). What was new was to link such emotions to historical epochs and to propose that these epochs could somehow be mined for their emotive content by emulating their style. Caroline van Eck has shown that the new interest in sensation and association made rhetorical style theory acutely relevant to architecture discourse and practice of the late 18th century (Eck et al. 1995: 89-106). With its ambition to provide operative precepts for architecture, moreover, this new sensationalist aesthetic would not only rely on but also transform the rhetorical idea of style.

Style and the Absolute: Goethe and Schiller
If style in the 1770s and 1780s was becoming a vehicle for epochal historiography and sensationalist aesthetics, it was also put to other uses. This we can glean from Johann Wolfgang Goethe's essay 'Einfache Nachahmung der Natur, Manier, Styl' (On simple imitation of nature, manner, style), published anonymously in the Teutsche Merkur in February 1789. And if the young Goethe had been close to Hirschfeld in his use of historical styles as emotive triggers, this more mature Goethe had a different take.
'Einfache Nachahmung' is not primarily about style but about imitation, more specifically how art may imitate nature. There are three modes of imitation, Goethe stated. The first is simple imitation, by which the artist simply copies forms and motifs from nature. The second is manner, by which the artist's personality and soul are brought into the work. Neither of these mimetic modes realize the potential of art, however. That only happens on the third level of imitation, which Goethe labelled style: Through imitation of nature, through the effort of creating a general language, through painstaking and thorough study … the artist finally reaches the point where he becomes increasingly familiar with the characteristic and essential features of things…. Then art will have reached its highest possible level, which is style and equal to the highest achievement of mankind. While simple imitation therefore depends on a tranquil and affectionate view of life, manner is a reflection of the ease and competence with which the subject is treated. Style, however, rests on the most fundamental principle of cognition, on the essence of things -to the extent that it is granted us to perceive this essence in visible and tangible form. (2016: 876) Simple imitation works in the forecourt of style, Goethe said; it is a necessary step towards true art, but far from sufficient. Personal manner, too, may be a stepping stone to style, yet must be distinguished from style proper. 9 Only when the artwork is purged of everything incidental and reaches a level of universal significance may one talk about style, understood as an expression of art's 'highest possible level ' (2016: 876). This exalted understanding of style is echoed by many of Goethe's contemporaries, not least Friedrich Schiller, who a few years later defined style as ' a complete elevation of the arbitrary into the general and the necessary' (Schiller 1793). 10 If Winckelmann and Hirschfeld could be said to leanwittingly or unwittingly -towards a relative understanding of style, the Weimar classicists put it back on a firm absolutist footing. By distinguishing style and manner, using the latter to as it were absorb all the relative aspects of art, they could reserve the term style for art's ideal potential. This distinction made its way into dictionary definitions in the early 1800s, together with a host of other more or less imaginative ways of differentiating absolute and relative style. Take for instance the above-mentioned 1817 entry from the Brockhaus Enzyklopädie: Style (stylos), originally the tool with which the ancients inscribed their writing onto hard materials; then the peculiar manner of expression in language or image (hence style in painting, sculpture, and architecture), subjective style; finally the most fitting manner of thought-expression in general, objective style. (Brockhaus 1817: 546) 11 Subjective style refers to artistic expression as it changes with artist, period, art form, or genre; in other words, the particular ways in which individuals, epochs, or cultures express themselves. It is comparable to what Goethe called manner, but expanded from an individual to an epochal concept. Objective style, on the other hand, denotes an ideal correlation between idea and form. Style in this latter sense describes a relationship, not -as does subjective style -a particular artistic expression. We will encounter this distinction in many forms throughout 19th-century architectural thinking.

Schlegel's Compromise
Style became subject to multiple differentiations towards the turn of the 18th century. On the one hand, there is a discernible historicization going on whereby style changes from referring to the mode of expression chosen by a speaker to the expressive outcome of a particular epoch. On the other hand, this relative notion of style is differentiated from style seen as an absolute principle, denoting the ideal correlation between idea and form. To align these conflicting interpretations and turn style into an operative aesthetic concept was one of the challenges for theorists of art and architecture at the beginning of the 19th century.
A particularly poignant response to this challenge is August Wilhelm Schlegel's essay 'Ueber das Verhaeltniss der schoenen Kunst zur Natur; ueber Taeuschung und Wahrscheinlichkeit; ueber Styl und Manier' ('On the relationship between fine art and nature; on illusion and truthfulness; on style and manner'), presented as a lecture in Berlin in 1802 and published in the Viennese magazine Prometheus in 1808. Like Goethe, Schlegel defined style not as an individual mode of expression (that would be manner) but rather an ideal correlation between the human spirit and the world at large: There is, then, necessarily something in the middle between art and nature that keeps them apart. This is called manner, when it is an obscure or confused medium that gives a false appearance to all the represented things; style, when it respects the rights of both art and nature. This is possible only through the work itself, with its own, as it were, imprinted elucidation. (Schlegel 2007: 266) 12 Schlegel linked the distinction between manner and style to their respective etymological origins. Manner derives via maniera from manus, hand, he told the reader, and is linked to a purely personal expression. The stylus, however, detached from the user's hand as an independent tool, lends a certain objectivity to its creations (Schlegel 2007: 268). The stylus does not belong to the artist but to the work, and is thus a suitable metaphor for the objective principle that Schlegel was after. Style is individuality sublimated into universality: ' a transformation of the inevitable limitation of the individual into a voluntary limitation, in accordance with an art principle ' (2007: 266). 13 At first glance, Schlegel promoted an absolute notion of style and repeated Goethe and Schiller's distinction between style and manner. Yet towards the end of the essay, a doubt creeps into Schlegel's text. It is possible, he asked, to speak about several styles without lapsing into mannerism? If there is only one truth, and style is the manifestation of truth, can we speak of style in the plural? His answer, somewhat unexpectedly, is yes. Because art is a complex phenomenon that can be approached from many angles, there is room for more than one style. Not only does every art form and genre have a different style; the individual artist may also develop his own version of the artistic principle, 'which develops with freedom and awareness into a practical system; into style ' (2007: 267). 14 Having thus fused Goethe's absolute notion of style with a far more relativized understanding of the term, Schlegel went one step further, into fully fledged historicization: Finally, art develops … gradually in time: this happens indisputably according to certain laws, even if we cannot always comprehend them within a limited period of time. Yet if we view an art corpus as a whole, and perceive the lawfulness of its development, then we are entitled to use the term style to characterize its different epochs. Style is then a necessary step in the development of art. (2007: 267) 15 The statement takes the reader by surprise. Goethe had defined style as the highest stage to which art is capable of rising, a position Schlegel seemed to share. And yet here he was, calling style simply a necessary step in the historical development of art. He even admitted the possibility of imperfect style (2007: 268); another blunt contradiction of the Weimar classicists' stylistic idealism. Yet Schlegel's reasoning was consistent. The different stages that art goes through are not random, he argued, but necessary steps in the lawful development of art. While certain periods (such as the contemporary one) may seem lost in mannerism, they are actually undergoing a necessary development towards fulfilment. By seeing art as an organic phenomenon, Schlegel could construe the history of art as a developmental continuum in which each stage was necessary and therefore, at least potentially, in possession of style.
Schlegel's aesthetic organicism captures a key feature of historicism. History, here, is understood as an organism (a tree, Herder famously proposed) complete at every stage yet evolving according to strict laws (Herder 2004;Eck 1994). The individuality of expressions found at different times and places are therefore not random mannerisms but manifestations of a lawful development. It is this historicist credo that allowed Schlegel to combine Goethe's absolute notion of style with a historicist idea of style as epochal expression. By introducing historical development rather than aesthetic perfection as the measuring stick of art and architecture, Schlegel introduced a concept of style that was both relative and universal. Recognizing that artists at different times, in different places, and of different temperaments do not necessarily strive towards the same ideal, Schlegel still insisted that their striving followed the same laws. Style, then, denotes the lawful correlation between historical conditions and artistic output, referring not to a particular expression but to a relationship with presumed universal validity.
Schlegel is a transitional figure between 18th-century idealism and an emerging historicism. As such, he is a good example of the persistent polarity built into the modern understanding of style. Schlegel's dual notion of style anticipates Viollet-le-Duc's famous distinction between style and the styles, discussed by Martin Bressani in this Architectural Histories issue on style. Viollet-le-Duc, too, promoted a universal concept of style ('the manifestation of an ideal based on a principle ' (1990: 232)), while at the same time acknowledging 'the styles' as a relative index to historical and geographical change. Schlegel's compromise, then, can be seen as paradigmatic for architectural discourse of the first half of the 19th century, establishing a pattern for how to think of style as both a relative, historical expression and a relationship with universal validity.
In Which Style? Heinrich Hübsch I am doing rather badly, so far, in my resolve to stick to style in architecture. But we are getting there. When the notion of style made its way into German architectural discourse in the first decades of the 19th century, it carried all the contradictory meanings outlined above. Art historians such as Carl Friedrich Rumohr lamented the confusion bitterly, urging his contemporaries to be more precise in their use of the term. He could not understand, he added wryly, how a lowly writing tool had come to denote so many wildly different aesthetic properties (1825: 297-98). 16 Despite its inbuilt contradictions, however, style promised to be a very useful concept to architecture. Not only did it facilitate analysis and comparison of architectural expression from different epochs, thus forming an indispensable tool for the historian; it also coined the relationship between form and idea, concept and execution, that was a main concern for practitioners, theorists, and critics alike. No wonder, then, that the definition and deliberation of style became a main architectural concern from the 1820s onwards.
The most famous invocation of style in early 19thcentury architecture is undoubtedly Heinrich Hübsch's manifesto In welchem Styl sollen wir bauen from 1828. This well-known text constitutes a direct attack on the idealist position. Hübsch confronted the futile idea that architectural beauty is absolute and disputed that antique style embodies ideal perfection (1992: 63). Aestheticians' attempts at establishing universal rules for art had been in vain, he declared, ending in ' empty sophism' (1992: 65). Hübsch himself adopted a more practical point of departure. Defining architecture a product of its purpose and its material, Hübsch set out to radically redefine style. And although he never entirely fulfilled his promise, the attempt is worth revisiting.
Having said that, Hübsch's definition of style in the second section of In welchem Styl counts among the great anticlimaxes in the history of architectural writing. It starts well enough, with Hübsch declaring didactically, 'We shall first define the concept of style'. In its familiar usage, he explained, 'style means something general, applicable to all buildings of a nation ' (1992: 66). Greek monuments are built in a Greek style, Moorish monuments in a Moorish style, etc. Instead of scrutinizing this usage, however, Hübsch adopted it as basis for the following false syllogism: 1) Style is something general; 2) The most general of all, as far as architecture is concerned, is the building's role as an enclosure (Abschliessung); 3) Therefore, style is about enclosure, or more specifically about the elements that make up the enclosure: 'walls, ceilings, piers or columns, doors, windows, roofs, and cornices ' (1992: 66). These are what Hübsch calls the elements of style.
Hübsch's (il)logical leap allowed for two things. Firstly, it turned the conversation about style from a theoretical to a practical question, in line with Hübsch's own preference for the 'practical view ' (1992: 65). Rather than pondering what Greekness or Moorishness actually consists of (and hence getting entangled in a philosophical discussion about zeit-and volksgeist), Hübsch could go straight to architectural form and analyse it with respect to purpose and material conditions. The overhanging roofs of northern medieval houses are shaped by climate, material, and need for protection, giving them a quite different form than, for example, the Mediterranean house. Similarly, the brick and mortar of the Romans allowed them to develop totally different forms (and hence a totally different style) than the Greeks, with their hard marble (1992: 68). These two building systems -the trabeated Greek and the arched and vaulted Roman -constitute the two original styles from which all other stylistic variation derives, Hübsch concluded (1992: 68).
Hübsch's aim was not an analysis of historical styles, however. His attempts at historical description and classification were at best half-hearted. The real agenda -and the second thing Hübsch's definition allowed for -was to establish ' a strictly objective skeleton for the new style' (1992: 99). This could not be the Greek style, since 'the formative factors that condition today's architecture are completely different -indeed almost diametrically opposed to those that affected the Greek style' (1992: 76). Hübsch elaborated: If we wish, therefore, to attain a style that has the same qualities as the buildings of other nations that are accepted as beautiful and are much praised by us, then this cannot arise from the past, but only from the present state of natural formative factors -that is: first, from our usual building material; second, from the present level of technostatic experience; third, from the kind of protection that buildings need in our climate in order to last; and fourth, from the more general nature of our needs based on climate and perhaps in part on culture. (1992: 71) Underlying Hübsch's argument is what I, in a previous essay, have called the 'principle of correspondence': the belief that there is and must be a strict correlation between historical conditions and architectural expression ( Hvattum 2013). In Hübsch's case, those historical conditions were defined largely in material terms, yet the logic is the same as the one we encountered in Winckelmann, when he insisted on the perfect correlation between the spirit of ancient Greece and Greek artefacts. What in Winckelmann remained an idealist principle, however, is in Hübsch thoroughly operationalized. Just as Greek style had sprung from particular conditions of time and place, the modern style must be based on 'the present state of the formative factors ', he thought (1992: 83). And while this modern style will necessarily be different from the Greek, both eras are governed by the same principle of correspondence, sharing, as it were, the same structural relationship between the era and its art. With Hübsch, the Sturm und Drang generation's zeitgeist had become an operative entity, not simply reflecting past epochs but making demands on its own time.
Hübsch reduced the notion of style to a question of coherence between material conditions and architectural form. In this he followed Rumohr, who in the first volume of Italienische Forschungen had brushed aside the entire idealist style theory and defined style simply as ' a submission, grown into a habit, to the intrinsic demands of the material' (Rumohr 1827: I, 87; see also Mallgrave 2005: 106). In other words, as long as we build in accordance with our own 'technostatic conditions' and our own needs, we will create in style. And since the modern conditions undeniably include the arch and the vault, our style must necessarily be based on these elements. Hübsch systematically analysed the vaulted style in all its variations: Roman architecture, Byzantine architecture, Rundbogenstil, and Spitzbogenstil, describing their respective qualities and discussing their potential for further use. His considerations were through-and-through practical. While the pointed arch may in some cases be structurally more efficient than a round arch, its height makes it impracticable for modern use. And while the steep roofs of Gothic architecture were impressive, their gradient makes it difficult to fix tiles or slates (1992: 95-97). After a series of such practical-minded considerations, Hübsch finally reached his conclusion, proclaiming early Christian Rundbogenstil as the most fitting model for the present conditions.
Hübsch's idiosyncratic defence of Rundbogenstil has been thoroughly analysed by Bergdoll (1983) and Herrmann (1992), among others. For our purposes, the structure of Hübsch's argument is more interesting than his particular stylistic preferences. Expanding style from a diagnostic to a prognostic tool, Hübsch turned style theory into an operative vehicle for design in quite a new way. If the rhetorical tradition had conceived style as a choice among established modes and genres, Hübsch saw it as an invention of potentially new modes, corresponding to new conditions. And if Goethe and Schiller had conceived style as the ultimate pinnacle of art, Hübsch saw it simply as an artistic manifestation of particular epochal forces, be they 'technostatic' or cultural. He agreed with Winckelmann that each period has its own style, but dismissed the art historian's latent idealism and idea of the universal perfection of Greek art. And while he adopted Schlegel's idea of style as primarily a relationship between an epoch and its art, he turned this relationship into an Erfindungsmethode for the invention of a new style.
It is tempting to see Hübsch's inventive aspirations as an anticipation of Gottfried Semper's 'formula for style', by which style was defined as a 'uniform result or function of several variable values that unite in certain combinations', a correlation Semper gave the mathematical expression Y = F(x, y, z, …), where Y stands for style, and x, y, z, etc., for the different coefficients influencing it (Semper 1884: 267). I will not go into Semper's style theory here, but only note that, for all its crudeness, the formula for style did manage to resolve the long-standing opposition between subjective and objective style. On the one hand, it expressed the uniqueness of each epochal style, asserting that the slightest change in historical or natural conditions must influence artistic style. On the other hand, the formula demonstrated that although historical conditions change, their interaction within the aesthetic process remains the same, constituting an ideal and ' objective' correlation. Hübsch's principle of correspondence aimed for a similar squaring of opposites, anticipating thus a historicist trope that would have a profound effect on 19thcentury architectural thinking.

Style and Contemporary Life: Friedrich Eisenlohr
Hübsch's musings on a new style were not kindly received. Wolfgang Herrmann has documented how the 1828 manifesto unleashed a furious debate over Hübsch's alleged materialism and reductivism (Herrmann 1992). '[H]e attaches to the term "style" a meaning that relates to material and construction, whereas in everyday language it is used in a spiritual sense only', remonstrated Rudolf Wiegmann in 1829 in Kunst-Blatt, making it clear that Hübsch's use of the term was an unfamiliar one (1992: 105). Wiegmann agreed with Hübsch in rejecting the Greek style, but disapproved of his adoption of Rundbogenstil. 'Our art must represent our time, just as past art represented its time', Wiegmann wrote, and since Rundbogenstil represented the middle ages, it was by definition not fitting for the present (1992: 109). Other critics were less categorical, empathizing with Hübsch's conclusion but finding his argumentation lacking. An example of the latter is found in a lecture held in 1830 at Hübsch's alma mater, the Polytechnische Schule in Karlsruhe. The speaker was Hübsch's assistant and later colleague, Friedrich Eisenlohr, an intriguing character known mainly for his innovative railway architecture and his invention of the cuckoo clock. But Eisenlohr was also an inspired thinker, attempting nothing less than to align Hübsch's practical aesthetics with an idealist conception of style.
Already in his title, Eisenlohr made it clear that he was adopting a wider scope than his senior colleague. His Rede über den Baustyl der neueren Zeit und seine Stellung im Leben der gegenwärtigen Menschheit (Speech on the architectural style of the modern age and its place in the life of contemporary humanity) indicates an interest, not merely in the 'technostatic' function of style but also its cultural significance. He began his lecture with a fairly conventional excursus on the origin of building in the cave and the tent. These primitive types were not the origin of architecture, however. The latter came about only when the human spirit rose above merely practical needs: Only then could [architecture] begin, when the human spirit felt an inner urge, a need, to externally re-present and express, in sensually perceptible works, that feeling of the divine which the intuition of nature had aroused in him. It began when the human being, in whom nature in its entirety seems to be reflected, breathed its own creative power into nature's sensually perceptible matter, and animated it. … It follows from this that architecture has more freedom in its shaping of natural matter than what mere physical need dictates (1833: [4][5]). 17 This idealist manifesto in miniature must have appeared as a rebuke to Hübsch, who was probably in the audience. Not only did Eisenlohr adopt a radically different definition of style than his colleague; he also returned to an idealist aesthetics that Hübsch himself had dismissed. Eisenlohr sounded in fact more like Schlegel (or indeed Hegel, albeit five years before the lectures on aesthetics were published) than he did Hübsch, presenting art and architecture as sensuous representations of the ideal (1833: [9]). 18 Like Schlegel and Hegel, Eisenlohr understood the ideal not as an unchanging but as an evolving historical entity. Architectural history is an expression of the human spirit in its historical development, he stated, and because the human spirit changes with the times, so must architecture: 'Given the difference between the spirit of different times and peoples, the works of architecture must also be different, insofar as they appear to be animated by that spirit' (1833: [10]). 19 Intimately linked to the zeitgeist, architecture evolves according to internal and external causes, wrote Eisenlohr, identifying the latter as religion, custom, use, climate, and building material. The inner cause, on the other hand, was only one, namely, 'that struggle of man to give expression to his built work analogous to that feeling of the ideal that he harbours deep within his soul' (1833: [11]). 20 The particular way in which architecture expresses these external and internal factors is what he called style.
After these general idealist musings, Eisenlohr became more specific. Human history falls into two main epochs, he stated, pre-Christian and Christian. The spirit of these two periods are different, even opposite, for while the pre-Christian era revolved around nature as its main principle, the Christian revolved around the spirit. This difference is manifest in architecture: 'If we observe the buildings from both these main epochs, we see their differences clearly manifested; their expression is quite analogous with the spirit of the times in which they were made ' (1833: [14]). 21 After this exemplary stating of the principle of correspondence, Eisenlohr turned to the question of contemporary relevance. His diagnosis was clear. The classical spirit was dead, 'long buried in the land of the obsolete' (1833: [15]). Given all the differences between antiquity and the modern age, the attempt to imitate classical architecture would inevitably lead to ' a false masquerade ' (1833: [19]). The Christian spirit, on the other hand, was alive and kicking. Contemporary German culture shared with its medieval past both the inner and many of the outer causes for style, Eisenlohr argued. Religion, custom, climate, and building material had remained relatively stable in the German cultural sphere, he thought, making the Christian style as relevant today as it had been in the Middle Ages (1833: [16]).
Eisenlohr, like Hübsch, promoted medieval architecture as the model for contemporary emulation. Unlike his colleague, however, Eisenlohr based his conviction not on tectonic conditions but rather on philosophical analyses. 'Architecture serves humanity, not the other way around', he stated: 'If a style does not evolve from the inner and outer life and needs of a people and a time, it will remain a remote copy, forever foreign to life and spirit ' (1833: 23). 22 Framing style as a matter of homeliness versus estrangement, Eisenlohr became an eloquent spokesman for what could be called an architecture of the zeitgeist. And although he distanced himself from Hübsch's reductive approach, their conclusions are remarkably similar. Both contributed to articulating the dominant imperative of 19th-century architecture: If style is the ideal correlation between a time and its art, then the overall aim of architecture is to define and shape our style: a style of the here and now. Karl Friedrich Schinkel put it in a similar manner in a diary note from 1830: 'Every epoch has left behind its architectural style, why should we not try to find a style also for our own time?' (Schinkel 1922: 194). 23

Paradoxes of Style in 19th-Century Architecture
The texts above harbour multiple conceptions of style. Yet in one way or another, they all relate to the distinction between subjective and objective style encountered in the 1817 edition of Brockhaus Enzyklopädie, i.e., between style as a particular artistic expressions (be they produced by a people, an epoch, or an individual) and style as a relationship -an ideal correlation between idea and form. The distinction would live on in 19th-century historicism, most notably in the distinction between epochal styles and what I have previously called the principle of correspondence. Both these style concepts would be put to use in 19th-century discourse, contributing to the shaping of architectural practice, theory, and historiography.
Last point first. The idea of style as the fingerprint of the zeitgeist made it, as we have seen, a useful historiographical tool. It allowed historians to present architecture as the tangible manifestation of cultural evolution and to group vast geographical and chronological expanses into tidy categories. This capacity to organize large quantities of knowledge in a succinct and logical manner was, as Petra Brouwer points out, one of the keys to the success of the new architectural history handbooks appearing from the 1840s onwards, with James Fergusson's Illustrated Handbook of Architecture from 1855 as the most famous example (Brouwer 2018). In the German-speaking context, this new history writing took off in the 1840s and '50s, with Franz Kugler's Handbuch der Kunstgeschichte (1841-42) and his later Geschichte der Baukunst (1856), Karl Schnaase's Geschichte der bildenden Künste (1843-64), and Wilhelm Lübke's Geschichte der Architektur von den ältesten Zeiten bis auf die Gegenwart (1855) as prominent examples, all based on style (Burioni 2016;Karge 2020). 24 As a taxonomic principle, style facilitated comparison across time and space, for while each style was unique, it displayed the same structural relationship between historical conditions and architectural form as any other style.
If epochal style was a useful historiographical concept, it also lent itself to other uses. In the 1780s Hirschfeld had already noted how different styles carried particular moods or atmospheres and how they could be used to evoke particular emotions in the contemporary viewer. This aesthetic sensationalism was put to use not least in 19th-century neo-Gothic architecture. Echoing Goethe's ecstatic description of Strasbourg cathedral from 1772, German writers such as Christian Ludwig Stieglitz, in 1820, praised the emotive potential of Gothic architecture and noted how classical architecture ' cannot possibly arouse such lofty and holy feelings' as those evoked by the ancient German cathedral (Germann 1973: 93). Schinkel went even a step further. Not only did he admire, in 1814, the 'soul-stirring style of ancient German architecture', he also envisioned that the perfection of the Gothic style still lay ahead, insofar as its development (a favourite argument in mid-19th century style debates) had never been brought to fulfilment. He anticipated the erection of a large sacred monument … in the soul-stirring style of ancient German architecture, an architecture whose ultimate perfection is to be achieved in the immediate future, since its development was broken off in its prime … with the result that the world is apparently now destined to perfect this art form. (Germann 1973: 91) The eclecticism of the 19th century relied heavily on such associationist thinking. By evoking different atmospheres and associations, style could transcend time and place, conjuring the spirit of ancient Greece in modern Bavaria or the mood of the Germanic middle ages in 19thcentury Prussia. Style confers a 'universal citizenship', wrote Hirschfeld, transporting us to other times and other places (1780b: 75, 2001: 287).
The universal citizenship of style is one of the most intriguing aspects of 19th-century historicism, matching the period's cosmopolitan and temporally complex way of thinking. Paradoxically, however, style understood as epochal expression would also be used to defend the exact opposite proposal. Hübsch himself anticipated this when he insisted that style is a result of the strict correlation between contemporary conditions and artistic expression. A new time, consequently, requires a new style -an assertion that would become a mantra for historicists and modernists alike. Style is thus no longer a choice but a destiny: a question of deciphering contemporary conditions so as to identify its correct equivalent in architectural form. It is this logic that would come to underpin the Vienna secession's motto 'Der Zeit ihre Kunst', Le Corbusier's ' esprit Nouveau', and Mies van der Rohe's 'will of the epoch'. It is a delicious paradox: modernism's radical rejection of style takes place within the conceptual framework of historicist style theory.  (Gumbrecht and Pfeiffer 1986: 93-114