MARCUS COCELIUS, the thirteenth emperor of Rome, was born at Narnia in Umbria A.D. 27, or, according to other authorities, in A.D. 32. He succeeded to the purple on the assassination of Domitian, September 18, A.D. 96, and, after a mild and equitable reign of sixteen months and nine days, died early in the spring of A.D. 98. Before his death he had adopted Trajan as his successor. (See Roman History.)