Antoninus Pius(86-161 A.D.), Roman emperor, 138-61. He had a notable public career and in 138 was adopted by Emperor Hadrian as his successor. His reign was generally peaceful and prosperous. He encouraged literature, architecture, and commerce.

Early in his reign, there was a rebellion in Scotland. In about 142, he ordered a defensive wall---which came to be known as the Wall of Antoninus---to be built across southern Scotland. The rebellion was crushed in 143. Antoninus adopted his nephew and son-in-law Marcus Aurelius as his successor.