The name "Amphitheatrum Flavian" was used for the Colosseum in ancient Rome because it was built during the reign of the Flavian dynasty. The Colosseum was constructed between 72 and 80 AD under the emperors Vespasian and Titus, both of whom were members of the Flavian family. The name "Amphitheatrum Flavian" was used to honor the Flavian dynasty and commemorate their construction of the iconic structure.