The more ancient account survived, however, he myth that Osiris, Horus, Seth, Isis and Nephthys (a less who plays but a minor part in the Osiris cycle) were all Iren of the earth-god Keb and the sky-goddess Nut, born on five consecutive days added on at the end of the year (the flied epagomenal days).
Technical.The standard year of the Ancient Egyptians consisted of twelve months of thirty days i each, with five epagomenal days, in all 365 days.
This Sothic period r era of 1460 years, during which the Egyptian New Years day travelled all round the Sothic year, is recorded by Greek and Roman writers at least as early as the 1st century B.C. The epagomenal days appear on a monument of the Vth Dynasty and in the very ancient Pyramid texts.