This chapter argues that international law as such did not exist in medieval European history as a codified legal norm as it did from 1648 onwards. The search for normativity in international political and diplomatic communication was a major political objective throughout the whole Middle Ages, from the Carolingian period up to the 15th century. At all times, practical challenges came first and theories on international normativities always followed practice. The instruments of a symbolic culture at the courts were useful to practically organize international diplomacy, as for instance during meetings between princes or at ceremonies of reception. To be a sovereign prince meant not to accept any superiors. Finally, sovereign princes could not accept the emperor’s nor the pope’s, nor anyone else’s superiority, but only an idea of an a priori and superior universal normativity.