John II Komnenos was a Byzantine Emperor who ruled from 1118 to 1143. He was the son of Alexios I Komnenos and is known for his efforts to stabilize the Byzantine Empire after a period of turmoil. His reign was marked by military campaigns against the Seljuk Turks and the strengthening of the empire's economy. John II was also a patron of the arts and education, promoting the revival of classical learning. He worked to improve relations with the Western European states, particularly through marriage alliances. His leadership helped to solidify the Komnenian dynasty's influence in the region.