A total solar eclipse that occurred on April 1, 2471 B.C. may have marked the end of the era of the great Egyptian pyramids. A study by Giulio Magli, an expert in Archaeoastronomy at the Milan Polytechnic Department of Mathematics, proposes a revolutionary new hypothesis that sheds light on a mysterious change in Old Kingdom funerary practices. The Fourth Dynasty (ca. 2600-2450 BCE) represents the pinnacle of Egyptian architecture, with the construction of the magnificent pyramids of Dahshur and Giza, including the extraordinary Great Pyramid of Cheops. However, during the short reign of Pharaoh Shepseskaf, there was a radical change: his tomb was not a pyramid, but a massive rectangular structure with raised ends, inspired by the archaic shrines of Buto, a sacred site in the Nile delta. Moreover, this tomb was not visible from Heliopolis, the center of Sun worship. The reasons behind Shepseskaf's radical departure from tradition have never been satisfactorily explained, until now. A new study conducted at the Department of Mathematics at the Polytechnic University of Milan, available on the arXiv platform, provides a new hypothesis based on Archaeoastronomy. Available data and calculations on historical eclipses show that on April 1, 2471 B.C., a significant and unexpected event occurred in the Nile delta: a total solar eclipse, with the path of totality almost centered on the sacred city of Buto. The Giza area and the capital, Memphis, were also very close to the zone of totality (>95%). The total eclipse of 2471 B.C.E. could have been interpreted as a divine omen, explains Professor Giulio Magli. This would have prompted Shepseskaf to break with tradition, reflecting a crucial symbolic and political change. The eclipse thus seems to have triggered a crisis that led to the end of the dominance of the solar cult in royal architectural choices”.