The dominant states in the Middle Ages.

If we take the entire period of the Middle Ages and take into account only the European context, then the dominant states were the following:
Byzantium, in fact, the successor to the Western Roman Empire, had a significant weight in world politics and acted both in the western and eastern vectors.
In many ways, the Italian republics were strong, like the Venetian, Genoese, Florentine. These were powerful states in terms of navigation, they had significant forces in world trade. For Central and Western Europe, the Holy Roman Empire can be called a significant powerful state.