Frederick II(24 January 1712-17 August 1786)was a King in Prussia (1740–1786) from the Hohenzollern dynasty. In his role as a prince-elector of the Holy Roman Empire, he was Frederick IV of Brandenburg. He was in personal union the sovereign prince of the Principality of Neuchâtel. He became known as Frederick the Great (Friedrich der Große) and was nicknamed der alte Fritz ("Old Fritz").
Interested primarily in music and not the arts of war during his youth, Frederick unsuccessfully attempted to flee from his authoritarian father, Frederick William I, with childhood friend, Hans Hermann von Katte, whose execution he was forced to watch after they had been captured. Upon ascending to the Prussian throne, he attacked Austria and claimed Silesia during the Silesian Wars, winning military acclaim for himself and Prussia. Near the end of his life, Frederick united most of his disconnected realm through the First Partition of Poland.
Frederick was a proponent of enlightened absolutism. For years he was a correspondent of Voltaire, with whom the king had an intimate, if turbulent, friendship. He modernized the Prussian bureaucracy and civil service and promoted religious tolerance throughout his realm. Frederick patronized the arts and philosophers, and wrote flute music. Frederick is buried at his favorite residence, Sanssouci in Potsdam. Because he died childless, Frederick was succeeded by his nephew, Frederick William II of Prussia, son of his brother, Prince Augustus William of Prussia.