Role: God of the sun
Appearance: Falcon-headed man with the sun disc on his head
Center of worship: Heliopolis
Relations with other gods: Father of Shu and Tefnut, and many other deities including Hathor and Sekhmet
Re had been the main sun god of Egypt since as far back as the Old Kingdom. During the fourth dynasty, pharaohs began to use the title "Son of Re" to remind everyone that they were not mere mortal humans but offspring of the #1 deity! References to Re were even included in the pharaohs' names so they could be associated with him further: Djedefre ("Enduring like Re"), Menkaure ("Eternal Like the Souls of Re"), Smenkhkare ("Vigorous is the Soul of Re"), and so on! In later times his role was combined with those of other gods including Amun, Atum, and Harakhte.
As the god of the sun, it was Re's job to make a daily trip across the sky. Starting at the eastern horizon, he sailed a special sun boat across the back of Nut, the goddess of the sky. Twelve hours later, he reached the western horizon, and then travelled another dozen hours through the underworld, where he faced many dangers until he could be reborn at the beginning of the next day.
Because he was such an important god, Re was involved in many Egyptian myths. In one myth, Isis outsmarted him to learn his "secret magic name." In another legend, Re is disgusted by the behavior of humankind so he sends his daughter Sekhmet to punish them, although she gets carried away and nearly wipes out the whole species! Another story that involves other gods and goddesses goes something like this...
Once upon a time, way back when Re was ruling on earth, he had overheard a prophecy that Nut (the goddess of the sky) would one day have a son that would replace him on the throne. Outraged, he cast a spell that forbade Nut to ever give birth to any child on any day of the year. Nut was naturally quite saddened by this so she turned to Thoth, the ibis-head god of wisdom and writing— because if anyone could outsmart the spell, it would be Thoth!
Thoth hatched a plan. He visited Khonsu, the moon god who loved to play the game senet. Thoth challenged Khonsu to a game, and Khonsu couldn't resist- after all, he was confident that he was the best senet player of all, and knew he would enjoy boasting about his victory over the god of wisdom. So when Thoth said that he wanted to play for some of Khonsu's moonlight, Khonsu was not at all worried.
Thoth easily won the first game and got an hour of moonlight as a reward. Anxious to win back his light, Khonsu agreed to another game... and another... and another... but he kept losing! When Thoth finally had won enough hours of light to equal five days, he called it quits. Khonsu was left so exhasted that from that moment on, he could no longer shine a full moon every night. As he got weaker and weaker, the moon got smaller and smaller, until he had to go into hiding to recuperate. As his strength returned, the moon would gradually become larger and larger until it became a full moon- but only for a night; then Khonsu would be sapped of all his strength and the moon would shrink again. So if you haven't figured it out by now, this is how the Egyptians explained how the moon changed phases!
Thoth returned to Nut with five extra days' worth of light. Thoth inserted these five bonus days between the last day of one year and the first day of the next. Since these days were not part of any year, Nut was able to use them to have her children despite Re's curse! Osiris— who would indeed go on to replace Re as the ruler on earth— was born on the first day. On the second day Nut had Set, followed in order by Isis on the third day, Nephthys on the fourth, and Harmachis on the fifth.
Initially, the ancient Egyptians had thought there were only 360 days in a year, so eventually their calendars got out of sync with their farming seasons. This myth helped account for the need for the five extra days to fix the calendar.