Who was the last reigning Byzantine Emperor?

Constantine XI Dragases Palaiologos, (8 February 1405 – 29 May 1453) was the last reigning Byzantine Emperor, ruling as a member of the Palaiologos dynasty from 1449 to his death in battle at the fall of Constantinople in 1453.

Following his death, he became a legendary figure in Greek folklore as the "Marble Emperor" who would awaken and recover the Empire and Constantinople from the Ottomans. His death marked the end of the Roman Empire, which had continued in the East (often known in historiography as the Byzantine Empire) for an additional 977 years after the fall of the Western Roman Empire in 476. The Empire had begun with the reign of Augustus in 27 BC, 1480 years prior.