In ancient Egyptian religion, the sacred bull regarded as the ba ('power' or physical manifestation) of the sun-god at Heliopolis. As one of several sacred bulls in Egypt, he was most closely associated with the sun god Re-Atum. There was only one Apis, Buchis, or Mnevis bull at any one time. Although not attested until later, the cult of Mnevis probably dated to the 1st dynasty (c 2925-2775 BC) or earlier. The Mnevis bull was either black or piebald in color, and in sculptures and paintings he was represented with a solar disk between his horns.