Atum (alternatively spelle Tem, Temu, Tum, and Atem) is an important deity in Egyptian mythology, whose cult centred on the city of Heliopolis. His name is thought to be derived from the word 'tem' which means to complete or finish. Thus he has been interpreted as being the 'complete one' and also the finisher of the world, which he returns to watery chaos at the end of the creative cycle. As creator he was seen as the underlying substance of the world, the deities and all things being made of his flesh or alternatively being his kas.