Early in the seventeenth century, J. J. Scaliger published his Thesaurus temporum, a book which combined critical editions of major Christian world chronicles with a manual of universal chronology, the Canones isagogici. In this work, unlike his previous chronological study De emendatione temporum, he sought to integrate the long past of Egypt into his scheme for synchronizing the histories of different nations, a scheme based on the innovative creation of a 7,980-year Julian Period. Scaliger derived his Egyptian chronology of kings and dynasties from the Aegyptiaca, a fragmentary history written in Greek by the Egyptian priest Manetho. This work satisfied his critical requirements far better than Herodotus' treatment of Egyptian history and chronology: “we find these dynasties more worthy of belief than Herodotus, a foreigner. For Manetho, an Egyptian by descent and dwelling, and a priest, dug them out of the ancient records of the Egyptian religion.”

Two centuries before the decipherment of any hieroglyphic texts, the Aegyptiaca possessed a unique authority because of Manetho's peculiar identity: an indigenous priest with direct access to Egyptian records, who nevertheless wrote in Greek. These luculentissima fragmenta (most brilliant fragments), as Scaliger called them, revealed to him “in an elegant order” (pulchro ordine) the long chronology of Egyptian records of the past. But as Anthony Grafton has shown, the fragments of the Aegyptiaca also cast light on the new context in which they were used, and especially the unresolved conflicts in Scaliger's approach to historical chronology.