Diocletian – Gaius Aurelius Valerius Diocletianus Augustus (244-312), Roman emperor from 284 to 305. In the Baedeker Pound was using (French edition 66), Diocletian is given credit for building the Arena, though newer evidence situates its construction in the Julio-Claudian period (14-54 AD). The Arena of Verona is older than the Colosseum in Rome, which was built on the same principle and finished in AD 80 (Bolla 14). It has nothing to do with Diocletian.