In The Pyramid Age, Northern Irish historian Emmet Sweeney provides evidence suggesting the pyramids were not built around 2350 BC, as is currently thought, but only around 800 BC. Sweeney's book argues that the dating of ancient history is often much more tenuous than most people realize, and that many of the puzzles and mysteries which confuse historians and archaeologists are solved as soon as the chronology is adjusted. He concedes his conclusions are revolutionary but says they are in line with a growing number of academics who are prepared to acknowledge that there may be something radically wrong with ancient chronology. Wolfgang Helck, Germany's foremost Egyptologist, recently admitted that work on chronology has clearly arrived at a crisis. Sweeney is adamant the pyramids could not have been built 4,000 years ago. The pyramids were partly constructed of hard granite and display in their design a knowledge of Pythagorean geometry, he points out. Yet in 2350 BC, the Egyptians only had copper and flint tools and such principles of mathematics had yet to be formulated. But modern scientists and engineers have demonstrated, repeatedly, that granite, basalt and diorite — all materials used by the pyramid-builders — can only be cut using carbon-steel tools. This mystery has led to all sorts of weird and wonderful theorizing not least the idea that the pyramids were built by aliens or Atlanteans. But revise the date of the pyramids' construction to around 800 BC, when steel tools were available and more sophisticated principles of geometry were widely understood, and the mystery is solved. Sweeney points out that the presently accepted chronology of Egypt is not based on science, but on venerated literary tradition. This chronology had already been established, in its present form, by the third century BC, when Jewish historians, utilizing the History of Egypt by the Hellenistic author Manetho, sought to tie in Egypt's history with that of the Bible. These efforts led to the equation of Menes, the first pharaoh, with Adam, the first man; and the consequential dating of the First Dynasty to around 4000 BC. The rest of Egyptian history, as outlined by Manetho, was made to fall in behind this starting-point. The chronology of Egypt, as outlined by these early scholars, was to become the traditional means of dating Egypt's past, and had already, by the 19th century, become so entrenched, that subsequent discoveries were unable to uproot it. As an illustration of this, Sweeney reminds us how Napoleon in 1798, before the Battle of the Pyramids, pointed to the Great Pyramid and told his men that forty centuries look down on you. Napoleon therefore placed the building of the monument around 2200 BC within little more than a century of the date still found in the textbooks. Yet Napoleon's speech was made over 20 years before Champollion had succeeded in deciphering the hieroglyphics and establishing the science of Egyptology! It is quite evident that Napoleon's estimate of the Pyramid's age was based on the traditional chronology; yet it is equally evident that the dates still found in the textbooks are based on the same system. Sweeney's work may prove to have far-reaching consequences for biblical scholarship. He insists the main reason why Egyptian history appeared to be silent about the great events described so vividly in the Bible, such as the story of Joseph (of the many-colored coat) and the Exodus, is that Egypt's chronology is out of sync with regard to that of the Bible. As a striking example of this, he shows how Hatshepsut, the female monarch who ruled as a pharaoh during the time of the mighty 18th Dynasty, was actually the legendary Queen of Sheba, who visited Solomon in Jerusalem. The connection between Hatshepsut and Solomon is in many ways obvious, says Sweeney, but was never made because in the textbooks Hatshepsut and Solomon are placed many centuries apart.