The Persian invasion in the early seventh century weakened Roman rule in Egypt, particularly the wealthy governing class. Only a decade after the Roman recovery of Egypt it was again invaded, by a two-pronged Arab army that took control of the country and, after a siege, of Alexandria. In many ways Egypt after the Arab conquest continued as it had been, with local elites and administrations running things on behalf of the small occupying force. If anything, elite power and rural dependency were reinforced by the new taxation system. Coptic language and literature flourished, with the gradual erosion of Greek as an imperial language, and the anti-Chalcedonian church of Egypt developed a distinct Coptic cultural and religious identity. Over time, however, a series of pressures and developments led to a wider use of Arabic in administration and in daily life, a decline in Coptic, and eventually to widespread conversion to Islam.