Elephantine Island is the site of ancient Abu (meaning both elephant and ivory in ancient Egyptian), both names a reminder of the island's once important ivory trade. At the beginning of the 1st dynasty (about 3,000 BC) a fortress was built on the island to establish Egypt's southern frontier. Abu soon became an important customs point and trading center. It remained strategically significant throughout the Pharaonic period as a departure point for the military and commercial expeditions into Nubia and the south. During the 6th dynasty (2345-2181 BC) Abu grew strong as a political and economic center and, despite periodic ups and downs, the island retained its importance until the Greco-Roman period.
As well as being a thriving settlement, Elephantine was the main cult center of the ram-headed god Khnum (at first the god of the inundation, and from the 18th dynasty worshipped as the creator of humankind on his potter's wheel), Satet (Khnum's wife, and guardian of the southern frontier) and their daughter Anket. Each year the rushing of the waters of the flood were first heard here on Elephantine. Over time religious complexes took over more and more of the island, so residential areas moved either further north on the island or to the east bank. The temple town of Abu received its coup de grâce in the 4th century AD, when Christianity was established as the imperial Roman religion. From then on, worship of the ancient gods was gradually abandoned and defensive fortifications were moved to the east bank, today's city of Aswan.