Alexandria is the third-largest city in Egypt after Cairo and Giza, the seventh-largest city in Africa, and a major economic center.Called the "Bride of the Mediterranean" by locals,[10] Alexandria is the largest city on the Mediterranean, the fourth-largest city in the Arab world, and the ninth-largest urban area in Africa. Alexandria was founded in c. 331 BC by Alexander the Great. Alexandria grew rapidly, becoming a major centre of Hellenic civilisation, and replacing Memphis as Egypt's capital during the reign of the Ptolemaic pharaohs who succeeded Alexander. It retained this status for almost a millennium, through the period of Roman and Eastern Roman (Byzantine) rule until the Muslim conquest of Egypt in 641 AD, when a new capital was founded at Fustat (later absorbed into Cairo).Alexandria was best known for the Lighthouse of Alexandria (Pharos), one of the Seven Wonders of the Ancient World, its Great Library (the largest in the ancient world), and the Necropolis, one of the Seven Wonders of the Middle Ages. Alexandria was the intellectual and cultural centre of the ancient Mediterranean for much of the Hellenistic age and late antiquity.The city was a major centre of early Christianity, and was the centre of the Patriarchate of Alexandria, which was one of the major centres of Christianity in the Eastern Roman Empire. In the modern world, the Coptic Orthodox Church, and the Greek Orthodox Church of Alexandria both lay claim to this ancient heritage.