[6] Atum is one of the most important and frequently mentioned deities from earliest times, as evidenced by his prominence in the Pyramid Texts, where he is sometimes syncretized with Ra to form Ra-Atum, and is portrayed as both a creator and father to the king throughout the collection of spells.
According to the Heliopolitan view, Atum originally existed in his egg within the primeval waters, being born during the primordial flood, becoming the source of everything that was created after him.
The Memphites (priests of Memphis), on the other hand, believed that Ptah created Atum in a more intellectual way, using his speech and thought, as told on the Shabaka Stone.
[8] Early myths state that Atum created the god Shu and goddess Tefnut by spitting them out of his mouth.
[16] In the Book of the Dead, which was still current in the Graeco-Roman period, the sun god Atum is said to have ascended from chaos-waters with the appearance of a snake, the animal renewing itself every morning.
Sometimes he is also shown as a serpent, the form he returns to at the end of the creative cycle, and also occasionally as a mongoose, lion, bull, lizard, or ape.
[24] In the Old Kingdom Atum was at the center of the Egyptian belief system, being partly responsible for the origins of existence, having created himself and everything else out of the primordial waters.
He is believed to have been present in ideology as early as predynastic times, becoming even more prevalent during the Old Kingdom as indicated by the pyramid texts in which he appears frequently.
He continues to be found in the Middle Kingdom, during which he is depicted in the Book of the Dead in which he appears in spells to help with the journey to the Afterlife.
[25] Ra would take center stage later on but as Atum was overshadowed, the people of ancient Egypt would continue to worship him through cultic rituals in which he is depicted as having close relationships with the king, as well as being represented through lizards on small reliquaries and amulets closer to the Late Period.