Roman emperor, born in Rome; distinguished himself under Trajan, his kinsman; was governor of Syria, and was proclaimed emperor by the army on Trajan's death in A.D. 117; had troubles both at home and abroad on his accession, but these settled, he devoted the last 18 years of his reign chiefly to the administration of affairs throughout the empire; visited Gaul in 120, whence he passed over to Britain, where he built the great wall from the Tyne to the Solway; he was a Greek scholar, had a knowledge of Greek literature, encouraged industry, literature, and the arts, as well as reformed the laws (76-138).