Hadrian, ha'dri-an, a Roman emperor. He was a nephew of Trajan, whom he succeeded. He reigned 117-138. He was a prudent man. He made numerous tours of inspection, strengthening the defenses and reorganizing the government of the provinces. He drew in the eastern boundary of the empire to the Euphrates. He is credited with originating Hadrian's Wall, or the Picts' Wall, as it is sometimes called. It was a combination of walls, earthworks, camps, roads, and stations, leading across Scotland from the mouth of the Tyne to the Solway. It lies farther south than Agricola's Wall, and, so far as may be judged from the ruins, was a work of military value. As seen from the north, it consisted first of a stone wall eight feet broad and twenty feet high, with turreted gates at intervals of a mile and numerous towers for the use of guards. One hundred twenty yards to the south of the stone wall, but parallel to it, stretched a double earthen rampart and ditch. Between the wall and the rampart ran a broad military road of perfect construction, in which fourteen fortified camps were located at intervals of about five miles. Hadrian was a famous builder. He founded the city of Adrianople, near Constantinople, and named it for himself. He built a large triumphal arch in Athens. At Rome he erected a magnificent mausoleum beyond the Tiber and constructed a new bridge leading to it. It is a huge circular tower 203 feet in diameter. It is now known as the castle of Sant' Angelo. Hadrian's Villa, near Rome, included a theater, a race course, booths, temples, an imperial palace, barracks, officers' quarters, and many other public buildings. The place was adorned with statuary, and was, no doubt, the most artistic spot in Italy.