Who reigned rome when the colosseum was being built?

The Colosseum was built during the reigns of Vespasian, Titus, and Domitian. Vespasian began construction of the Colosseum in 72 AD, and it was completed in 80 AD under the rule of Titus. Domitian made some modifications to the Colosseum, including adding the upper level of seating, during his reign from 81 to 96 AD.