Hadrian (hā´drēən), AD 76–138, Roman emperor (117–138), b. Spain. His name in full was Publius Aelius Hadrianus. An orphan, he became the ward of Trajan. Hadrian distinguished himself as a commander (especially in Dacia) and as an administrator. Trajan's choice of Hadrian as his successor, announced after his death, caused some discontent in Rome. His reign was vigorous and judicious, and he ruled over a prosperous and relatively peaceful era. Hadrian proved his military skill in pacifying (118) Moesia. Abandoning Trajan's aggressively expansionist policy in Asia, he withdrew to the boundary of the Euphrates. In Palestine, however, he proved himself ruthless. His Romanizing policy aroused opposition there, especially when he excluded the Jews from Jerusalem. He put down (AD 132) the insurrection of Bar Kokba with great severity; the ensuing war (132–135) was the most difficult of his reign. In Rome he was generous in offering circuses and in giving alms to the poor, and he enlarged and reformed the civil service.
Hadrian traveled extensively in the empire, interesting himself in all the local affairs of state and adorning the provincial cities. In Germany he built great protective walls, and in Britain (where he had visited c.121) he had Hadrian's Wall constructed. He built a temple of Jupiter Capitolinus on the site of the ruined Temple at Jerusalem and renamed Jerusalem Colonia Aelia Capitolina. He also built the Arch of Hadrian in Athens, and in Rome he rebuilt the Pantheon, added to the Roman Forum, and erected a mausoleum (now Castel Sant'Angelo). His last years were spent more or less quietly in Rome and in his villa at Tibur (which has been excavated), cultivating the arts. He was learned in Greek and accomplished in poetry and music. Hadrian also patronized artists, and his love for the doomed young Antinoüs was memorialized by sculptors and architects. As his successor he chose Antoninus Pius.
See S. Perowine, Hadrian (1987); M. T. Boatwright, Hadrian and the City of Rome (1989); A Everitt, Hadrian and the Triumph of Rome (2009).