Hadrian

Becomes emperor at 41. Trajan's wife Plotina probably engineered the succession. Within days, four leading senators are put to death. Hadrian claims he didn't order it. The Senate doesn't believe him and never forgives him.

Begins construction of Hadrian's Wall across the width of Britain. Seventy-three miles, coast to coast, with a fort every Roman mile. It marks the northern boundary of the empire. He doesn't want more territory. He wants defensible borders. This is a fundamental break from Trajan's expansionism.

His companion Antinous drowns in the Nile in Egypt. Hadrian is devastated. He founds a city, Antinoopolis, at the site of the drowning and establishes a religious cult around the dead youth. Temples are built across the empire. More statues survive of Antinous than of almost any other figure in antiquity.

The Bar Kokhba revolt erupts in Judea after Hadrian bans circumcision and plans to build a Roman temple over the ruins of the Jewish Temple in Jerusalem. The war lasts three years. Roman losses are so heavy that Hadrian omits the customary "I and the legions are in health" from his report to the Senate. He renames Judea "Syria Palaestina."

Dies at Baiae at 62 after years of chronic illness. His marriage was childless and unhappy. He adopts Antoninus Pius as successor on the condition that Antoninus adopt Marcus Aurelius. The Senate wants to damn his memory. Antoninus talks them out of it. Historians later count Hadrian among the Five Good Emperors.