Ubi papa, ibi Roma: Rome may not always be in Rome, for Rome is wherever the Pope is in residence. This 13th Century adage underlines the identification between city and sovereign; the capital is defined by its function of political command. The capital in question was a strange choice in the Middle Ages for, while seeing itself as the caput mundi, it had difficulty being recognized as a mere regional capital. What, therefore, was a capital city in the Middle Ages? We must look beyond the false evidence that comes from a centralized Paris that goes back over a thousand years or to a lesser degree London: things are more complex than they appear at first. It is true that we find the Roman model of the imperial capital persisting under various forms with Constantinople, Baghdad and Cairo. Nevertheless, when the Carolingians re-established the Empire in 800, they did not go back to the model of the imperial capital. In fact, what characterized the institutional and territorial experience of the Medieval West was the dispersion rather than the concentration of the various functions of a capital. The 36th Congress of the SHMESP took place in Istanbul, at the invitation of the French Institute of Anatolian Studies. Here we found a décor suited to our endeavor. It is a historical and monumental setting, at the heart of some of the political experiences compared and contrasted by our contributors over a long-time scale. For writing the history of capital cities leads one, inevitably, to focus on the diversity of the models of the emergence of the state. The relationship between the palace and the city, as well as the movement of the centers of gravity of territorial constructions, the abandon of and return to various capitals – all this shows a number of different configurations of power. From this point of view the question of symbolic markers is essential. A city is able to convince that it controls various functions of commandment through image and ritual, words and walls, by the mobilization of memory and the building of impressive monuments. It can continue enjoying the prestige of a defunct capital for very long. By concentrating on the simultaneously material and ideal aspects of administrative centralization in urban society our contributors have attempted to restore a richness of meaning to that seemingly anodyne term “capital city” in the Middle Ages.