Who was the most powerful German king?

The most powerful German king is often considered to be Otto I, who ruled from 936 to 973. He successfully united much of Germany and expanded his influence over Italy, ultimately becoming the first Holy Roman Emperor in 962. Otto's reign marked the consolidation of the German monarchy and the strengthening of the church's role in governance, establishing a precedent for future emperors. His achievements laid the groundwork for the medieval German state and its power dynamics.