Enki () is the Sumerian god of water, knowledge ("gestú"), mischief, crafts ("gašam"), and creation ("nudimmud"), and one of the Anunnaki. He was later known as Ea in Akkadian (Assyrian and Babylonian) mythology. He was originally patron god of the city of Eridu, but later the influence of his cult spread throughout Mesopotamia and to the Canaanites, Hittites and Hurrians. He was associated with the southern band of constellations called "stars of Ea", but also with the constellation AŠ-IKU, "the Field" (Square of Pegasus). Beginning around the second millennium BCE, he was sometimes referred to in writing by the numeric ideogram for "40", occasionally referred to as his "sacred number". The planet Mercury, associated with Babylonian "Nabu" (the son of Marduk) was, in Sumerian times, identified with Enki.