son and successor of Trajan, also a
Spanish-born Roman Emperor, Hadrian fomented industry and the
arts and greatly expanded the cultural life of the empire. He
personally visited the far corners of his dominions and improved
trade and administration. His was an innovating and intelligent
administration which earned him the title of "Optimus Princeps"
(Best Governor). He built the Mausoleum of Adrian, now the castle
of Saint Angelo and protected the empire from the barbarian incursions.