The Message of the Sphinx (Keeper of Genesis in the United Kingdom) was a book written by Graham Hancock and Robert Bauval in 1996 which argued that the creation of the Sphinx and Pyramids can be pushed back as far as 10,500 BC using astronomical data.
Working from the premise that the Giza complex encodes a message, they begin with recently discovered geological evidence indicating that the deep erosion patterns on the flanks of the Sphinx were caused by 1000 years of heavy rain. Such conditions last existed in Egypt at the end of the last ice age, about 10,000-9,000 BC, meaning that the Sphinx may be more than 12,000 years old (not the generally accepted 4500 years). The authors go on to suggest, using computer simulations of the sky, that the pyramids, representing the three stars of Orion's Belt, along with associated causeways and alignments, constitute a record in stone of the celestial array at the vernal equinox in 10,500 BC. This moment, they contend, represents Zep Tepi, the "First Time," often referred to in the hieroglyphic record. They claim that the initiation rituals of the Egyptian pharaohs replicate on Earth the sun's journey through the stars in this remote era, and they suggest that the "Hall of Records" of a lost civilization may be located by treating the Giza Plateau as a template of these same ancient skies.
This theory is dismissed by many archaeologists as they believe there is no evidence to support the existence of such an ancient civilization. This is, however, disputed by Bauval and Hancock through in their claims on the architecture and design of the Pyramids and the Sphinx.