Fred·er·ick I 
(frĕdrĭk, -ər-ĭk) Known as Frederick Bar·ba·ros·sa (bär′bə-rŏsə, -rôsə) 1123?-1190.
(frĕdrĭk, -ər-ĭk) Known as Frederick Bar·ba·ros·sa (bär′bə-rŏsə, -rôsə) 1123?-1190. Holy Roman emperor (1152-1190). After quelling the rebellious German nobility, he attempted to establish his authority in Italy but was forced to concede the sovereignty of the Papal States (1177). He drowned while leading the Third Crusade.