probably centered around Talmis (Kalabsha), but before 450 they were already driven out of the Nile Valley by the Nobatians. The latter eventually founded a kingdom on their own, Nobatia. By the sixth century there were in total three Nubian kingdoms: Nobatia in the north, which had its capital at Pachoras (Faras); the central kingdom, Makuria centred at Tungul (Old Dongola), about south of modern Dongola; and Alodia, in the heartland of the old Kushitic kingdom, which had its capital at Soba (now a suburb of modern-day Khartoum). Still in the sixth century they converted to Christianity. In the seventh century, probably at some point between 628 and 642, Nobatia was incorporated into Makuria. Between 639 and 641 the Muslim Arabs of the Rashidun Caliphate conquered Byzantine Egypt. In 641 or 642 and again in 652 they invaded Nubia but were repelled, making the Nubians one of the few who managed to defeat the Arabs during the Islamic expansion. Afterward the Makurian king and the Arabs agreed on a unique non-aggression pact that also included an annual exchange of gifts, thus acknowledging Makuria's independence. While the Arabs failed to conquer Nubia they began to settle east of the Nile, where they eventually founded several port towns and intermarried with the local Beja. From the mid eighth to mid eleventh century the political power and cultural development of Christian Nubia peaked. In 747 Makuria invaded Egypt, which at this time belonged to the declining Umayyads, and it did so again in the early 960s, when it pushed as far north as Akhmim. Makuria maintained close dynastic ties with Alodia, perhaps resulting in the temporary unification of the two kingdoms into one state. The culture of the medieval Nubians has been described as "Afro-Byzantine", but was also increasingly influenced by Arab culture. The state organisation was extremely centralised, being based on the Byzantine bureaucracy of the sixth and seventh centuries. Arts flourished in the form of pottery paintings and especially wall paintings. The Nubians developed an alphabet for their language, Old Nobiin, basing it on the Coptic alphabet, while also utilizing Greek, Coptic and Arabic. Women enjoyed high social status: they had access to education, could own, buy and sell land and often used their wealth to endow churches and church paintings. Even the royal succession was matrilineal, with the son of the king's sister being the rightful heir. From the late