Rome is said to have reached its zenith in security and expansion during the period of the "Five Good Emperors" (96 to 180 CE.). The time of Trajan (98 to 117 CE.) was a particular epoch of conquest and building, highlighted by the construction of Trajan's Markets and enormous Forum, the ruins of which still dominate the center of Rome. Trajan's successor, Hadrian, was a horse of a different color. He was himself an architect obsessed with circles, squares, spheres, and cubes. And his fondness for Greek art bordered on manic.