Bat is a very ancient goddess; the earliest evidence of her dates to the late Pre-Dynastic period. She was a cow-goddess of the sky with the power to see the past and into the future. This ability is referred to in the Pyramid Texts, where she was called "Bat, with her two faces." The deceased pharoah associated himself with Bat in this form. Later, she seemed to be the personification of the sistrum.
Bat was the chief deity for centuries in the 7th nome of Upper Egypt. During the Middle Kingdom, she was superseded by Hathor, who dominated the 6th nome - just next door.
Bat was not depicted very often in Egyptian artwork, however she was more commonly seen in amulets. She was shown as a woman with a human face, bovine ears and curly horns which emerged from her temples. She is most likely the cow-goddess seen at the top of the famous Narmer palette, which celebrated the unification of Upper and Lower Egypt. Bat is also famously seen on a unification pectoral in which she, as a sistrum), sits between Horus and Seth. Horus and Seth were the gods of Upper and Lower Egypt. Her image influenced the cult of Hathor.