Towards the end of the fourth millennium BC several independent city-states were unified to form a single state, marking the beginning of over 3,000 years of pharaonic civilisation in the Nile Valley. Fertile earth left behind after the yearly Nile flood provided the basis for Egypt’s agricultural prosperity, a key factor in the longevity of the civilisation. Impressive monuments were erected in the name of kings, from monumental temples for the gods to the pyramids marking the burials of rulers. The British Museum collection includes statuary and decorated architecture from throughout pharaonic history, often inscribed with hieroglyphs. Many other aspects of ancient Egyptian culture are represented: coffins and mummies of individuals, but also furniture, fine jewellery and other burial goods. These reflect the practice of lavish burials for the wealthy, which included the royal family, government officials and the priesthood.