"Europe" as a cultural sphere is first used during the Carolingian dynasty to encompass the Latin Church (as opposed to Eastern Orthodoxy). Military unions of "European powers" in the medieval and early modern period were directed against the threat of Islamic expansion. Thus, in the wake of the Fall of Constantinople to the Turks in 1453, George of Podebrady, a Hussite king of Bohemia, proposed in 1464 a union of European, Christian nations against the Turks.[1]