Hadrian (/ˈheɪdriən/ HAY-dree-ən; Latin: Publius Aelius Hadrianus [(h)adriˈjaːnus]; 24 January 76 – 10 July 138) was Roman emperor from 117 to 138. Hadrian was born in Italica, close to modern Seville in Spain, an Italic settlement in Hispania Baetica; his branch of the Aelia gens, the Aeli Hadriani, came from the town of Hadria in eastern Italy. He was a member of the Nerva–Antonine dynasty.

Early in his political career, Hadrian married Vibia Sabina, grandniece of the ruling emperor, Trajan. The marriage and Hadrian's later succession as emperor were probably promoted by Trajan's wife Pompeia Plotina. Soon after his own succession, Hadrian had four leading senators unlawfully put to death, probably because they seemed to threaten the security of his reign; this earned him the senate's lifelong enmity. He earned further disapproval by abandoning Trajan's expansionist policies and territorial gains in Mesopotamia, Assyria, Armenia, and parts of Dacia. Hadrian preferred to invest in the development of stable, defensible borders and the unification of the empire's disparate peoples as subjects of a panhellenic empire, led by Rome.