Sham El-Nessim: What is the story of the oldest “spring festival” that Egyptians have celebrated for thousands of years?

The Egyptian life in ancient times was not limited to performing religious rituals, devoid of enjoying the joys of life and spreading the spirit of joy. He was keen on more than one occasion to emphasize the concept of joy in his inscriptions and texts. Among those holidays, “Sham El-Nessim”, the oldest popular holiday, so what is its story?