The murder of Osiris (part1)

In the days before Ra had left the earth, before he had begun to grow old, his great wisdom told him that if the goddess Nut bore children, one of them would end his reign among men. So Ra laid a curse upon Nut - that she should not be able to bear any child on any day of the year.

Full of sorrow, Nut went for help to Thoth, the thrice-great god of wisdom and magic and learning, Ra's son, who loved her. Thoth knew that the curse of Ra, once spoken, could never be recalled, but in his wisdom he found a way of escape. He went to Khensu, the Moon-god, and challenged him to a contest at draughts. Game after game they played and always Thoth won. The stakes grew higher and higher, but Khensu wagered the most, for it was some of his own light that he risked and lost.

At last Khensu would play no more. Then Thoth the thrice-great in wisdom gathered up the light which he had won and made it into five extra days which for ever after were set between the end of the old year and the beginning of the new. The year was of three hundred and sixty days before this, but the five days which were added, which were not days of any year, were ever afterwards held as days of festival in old Egypt.

But, since his match with Thoth, Khensu the moon has not had enough light to shine throughout the month, but dwindles into darkness and then grows to his full glory again; for he had lost the light needed to make five whole days.