During the first twelve years after entry into effect of Rome Treaties in 1958, the then European Communities succeeded in establishing their first common policies, completing the customs union, and unifying administrative bodies. At the same time however, European leaders failed to constitute a political union, enlarge the Communities to the United Kingdom and establish the majority vote in the Council of Ministers. All scholars agree that European integration of this period was heavily int1uenced by the French President, De Gaulle's European policy, which was in general explained with reference to the classical realism, De Gaulle based its European policy upon French raison d'Etat and would like to have restructured the European Communities into a unified political entity under French leadership. This classical realist interpretation was later challenged by several integration theories which emerged since the mid 1980s. Liberal intergovernmentalism put into doubt the assumption that state leaders alone decided and formulated national interests. Neo-functionalism and institutionalism both criticized realism for underestimating the importance of supranational institutions and their leaders in the European integration. The author therefore aims to reevaluate the classical realist interpretation of European integration between 1958 and 1969 and examine the abovementioned criticism against this interpretation before drawing into some conclusions. According to the author's findings, classical realism still prevails over the intergovernmentalism, neofunctionalism and institutionalism in the explanation of successes and frustrations of European integration between 1958-1969, though it should have paid more attention to the power of perception as required by sociological institutionalism and constructivism.