Hadrian spent more time away from Rome than any emperor before or after him. In twenty-one years of rule, from 117 to 138 AD, he made two extended tours of the empire’s provinces, personally inspecting frontiers, reviewing troops, visiting cities, correcting administrative abuses, and leaving behind a physical record of his passage in the form of temples, baths, aqueducts, and the walls and frontier fortifications whose most famous example still bears his name. He was the most traveled of emperors, the most architecturally prolific, and the most systematically interested in the practical realities of governance at the provincial level. He was also the most controversial figure of the Antonine dynasty, for reasons that have as much to do with his personality as with his policies.