The Ptolemaic Kingdom in and around Egypt began following Alexander the Great's conquest in 332 BC and ended with the death of Cleopatra VII and the Roman conquest in 30 BC. It was founded when Ptolemy I Soter declared himself Pharaoh of Egypt, creating a powerful Hellenistic state stretching from southern Syria to Cyrene and south to Nubia. Alexandria became the capital city and a center of Greek culture and trade. To gain recognition by the native Egyptian populace, they named themselves the successors to the Pharaohs. The later Ptolemies took on Egyptian traditions by marrying their siblings, had themselves portrayed on public monuments in Egyptian style and dress, and participated in Egyptian religious life. Hellenistic culture thrived in Egypt until the Muslim conquest. The Ptolemies had to fight native rebellions and were involved in foreign and civil wars that led to the decline of the kingdom and its annexation by the Roman Empire.