John II Comnenus was a Byzantine Emperor who ruled from 1118 to 1143. He was the son of Alexios I Comnenus and is known for his efforts to restore the Byzantine Empire's strength after a period of decline. His reign was marked by military campaigns against the Seljuk Turks and the Normans, as well as diplomatic relations with Western powers. John II was also a patron of the arts and education, promoting the revival of classical learning. He implemented administrative reforms that improved the efficiency of the empire. His reign is often considered a high point in the Comnenian dynasty, characterized by stability and prosperity.