Hadrian , or Adrian (Publius AElius Hadri-anus), a Roman emperor, born in Rome, Jan. 24, A. D. 76, died July 10, 138. His father, a Roman senator, married the aunt of Trajan; and when he died, Trajan, who had not yet succeeded to the empire, became one of Hadrian's guardians. The emperor Nerva adopted Trajan, and the next year died, and Hadrian travelled from upper to lower Germany, and was the first to announce the event to the new emperor. He next married Julia Sabina, granddaughter of Trajan's sister; and through this new connection, joined to the favor of the emperor's wife Plotina, he rose rapidly to various high offices at Rome, being quaestor in 101, tribune of the people in 105, praetor in 107, and legatus proetorius of Lower Pannonia in 108. He accompanied Trajan in most of his expeditions, and distinguished himself in the second war against the Dacians (104-106). Trajan made him his private secretary, and probably selected him as his heir. When Trajan died, Hadrian was in command of the armies of the East, and was proclaimed emperor at Antioch, Aug. 11, 117. He immediately wrote to the senate apologizing for this haste, and asking their sanction of his election, which they at once gave. Hadrian's policy was pacific.

He renounced the conquests made by Trajan east of the Euphrates, concluded a treaty with the Parthians, and returned to Rome, where he celebrated a triumph in honor of his predecessor (118). Some warlike movements of the Sarmatians now drew him toward Dacia, but his progress was checked by intelligence of the discovery of a conspiracy at Rome, led by men of high rank. He directed the chief conspirators to be put to death, a severity which offended many. To recover his popularity he cancelled the arrears of taxes for the last 15 years, and assured the senate that he would never again put to death a senator without their consent. In 119 he began his tour through the Roman empire, visited Gaul and Germany, and in Britain built a rampart of earth about CO m. long for the defence of the Roman province, extending from Solway frith to the North sea near the mouth of the Tyne. He then returned through Gaul, spent a winter in Spain, crossed into Mauritania, visited Egypt and western Asia, and finally paused at Athens for three years, where he was initiated into the Eleusinian mysteries, and presided at the public games. In this journey he won the favor of the provincials by his liberality, and by various public works which he planned and executed for their benefit.

The Jews having revolted in 131, he punished them with great severity. Judea was desolated and reduced almost to a wilderness; the Jews were expelled from Jerusalem, and were forbidden to return thither, a Roman colony being planted in their place. His health declining, he chose Titus Aurelius, afterward known as Antoninus Pius, his heir, but obliged him to adopt the son of AElius Verus, and also M. Annius Verus, the future Marcus Aurelius. He had built a magnificent villa near Tibur, where he now passed much of his time. As death approached, his mind became affected, and he grew suspicious and cruel. He was an able and generally a wise ruler. His literary attainments were considerable; he wrote and spoke with eloquence, and left numerous works in prose and verse, all of which are lost except a few epigrams.