Colosseum or Coliseum, Ital. Colosseo, common name of the Flavian Amphitheater in Rome, near the southeast end of the Forum, between the Palatine and Esquiline hills. Begun by Vespasian, c.A.D. 75, and completed by his son Titus in A.D. 80, it is the most imposing of Roman antiquities. The vast four-storied oval is 617 ft (188 m) by 512 ft (156 m), much of which is still standing; it had tier on tier of marble seats accommodating c.45,000 spectators. It encloses an arena measuring 250 ft (76 m) by 151 ft (46 m) where gladiatorial combats were held (see gladiators) until 404. According to tradition, persecuted Christians were thrown there to beasts. The Colosseum has been damaged several times by earthquakes.

Flavian Amphitheater in Rome, erected circa AD 70–82 under the emperors Vespasian and Titus. The name Colosseum was applied some time after the 8th century because of its immense size and capacity, holding some 50,000 people. Unlike earlier amphitheaters, which were nearly all dug into hillsides for extra support, the Colosseum is a freestanding oval colonnaded structure of stone and concrete. It was the scene of combats between gladiators, contests of men with animals, and even mock naval engagements. The Colosseum was damaged by lightning and earthquakes in medieval times and, even more severely, by vandals. A restoration project was undertaken in the 1990s, and in 2000 the Colosseum staged a series of plays that marked the first time in more than 1,500 years that live performances had been held there.

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