 He was the longest-reigning German monarch when in 1493, after ruling his domains for more than 53 years, he was succeeded by his son Maximilian I.During his reign, Frederick concentrated on re-uniting the Habsburg "hereditary lands" of Austria and took a lesser interest in Imperial affairs.Nevertheless, by his dynastic entitlement to Hungary as well as by the Burgundian inheritance, he laid the foundations for the later Habsburg Empire.