Byzantium was conquered in 1453. They no longer exist in 1500s

Quite a few players has been asking us about similar scenarios - rebellion of Ireland, Recreation of Byzantium. So there’s a very good chance we’ll add these as epic quests that players can send their armies to do.

Kon I love the Byzantines too so good idea. I was known
to you as Masterlee

While Byzantium/Eastern Rome no longer exists due to the Ottoman Conquest, the "Rum" Millet remains, and there were still "Byzantine" pretenders, some of whom with official state support. In particular the Gonzaga of Mantua actually had their own Italian state and officially pursued the idea of a Roman restoration in Constantinople, citing their descent from the Palaiologos.