The Sassanid Empire was the final pre-Islamic Persian Empire and the chief rival of the Roman and Byzantine Empires for over 400 years. The Sassanids saw themselves as the true heirs to the Achaemenids (Cyrus and Darius) and revived traditional Persian culture and the Zoroastrian religion. They were famous for their heavy cavalry, the Cataphracts, who were armored from head to toe in mail. Their capital, Ctesiphon, featured the 'Taq Kasra,' the largest single-span brick arch in the world. Sassanid art and architecture heavily influenced the later Islamic Golden Age, and their administrative systems served as the blueprint for the Abbasid Caliphate. They fell in 651 CE following the Arab conquests, ending over a millennium of ancient Persian imperial rule.