The goddess of
love,
joy, and
beer, too. But it was not always so.
Hathor was a daughter of the great god Re, who ruled the heavens. One day he became displeased with the behavior of the people of the Nile, and decided to teach them a lesson. He cast his fiery eye upon Hathor, and sent her, in the form of the lioness Sakhmet, to destroy the unfaithful.
Sakhmet/Hathor went about her duty with abandon, killing until the fields ran red with blood. She began to drink the blood, and soon went completely berserk, killing the evil and the good alike.
Now old Re had only meant to punish the people, not wipe them out, but there was no way to recall the beast that he had created. She had to stop herself.
Re decided to trick her. He dipped into his godly private stock of beer, and dyed 7000 casks of it with pomegranate juice. This he spilled on the ground where Sakhmet/Hathor was headed. Thinking it was blood, she drank and drank, until she finally passed out. When she awoke, she was once again the graceful, protective Hathor, and the secret of beer was known to the people.
After that, the worship of Hathor always involved getting stinking drunk on red beer, amid much singing and dancing. The hidden meaning behind the revelry, though, was that it kept the ravening Sakhmet at bay...