Josephus ( Antiquities 1.3) says that the pre-diluvians lived a long time so they could make astronomical discoveries that required a lifetime of at least 600 years: “God afforded them a longer time of life on account of their virtue, and the good use they made of it in astronomical and geometrical discoveries, which would not have afforded the time of foretelling [the periods of the stars] unless they had lived six hundred years; for the great year is completed in that interval.”

Josephus claims that he has supporting evidence from other writers for this theory: “Now I have for witnesses to what I have said, all those that have written Antiquities , both among the Greeks and barbarians; for even Manetho, who wrote the Egyptian History , and Berosus, who collected the Chaldean Monuments , and Mochus, and Hestieus, and, besides these, Hieronymus the Egyptian, and those who composed the Phoenician History, agree to what I here say: Hesiod also, and Hecatseus, Hellanicus, and Acusilaus; and, besides these, Ephorus and Nicolaus relate that the ancients lived a thousand years. But as to these matters, let every one look upon them as he thinks fit.”

This knowledge was delivered to the post-flood world through Noah, who passed it on to his descendants, including Abram.

Abram (hailing from Chaldea) was the one who brought knowledge of astronomy to the Egyptians: “For whereas the Egyptians were formerly addicted to different customs, and despised one another’s sacred and accustomed rites, and were very angry one with another on that account, Abram conferred with each of them, and, confuting the reasonings they made use of, every one for their own practices, demonstrated that such reasonings were vain and void of truth: whereupon he was admired by them in those conferences as a very wise man, and one of great sagacity, when he discoursed on any subject he undertook; and this not only in understanding it, but in persuading other men also to assent to him. He communicated to them arithmetic, and delivered to them the science of astronomy; for before Abram came into Egypt they were unacquainted with those parts of learning; for that science came from the Chaldeans into Egypt, and from thence to the Greeks also.” By Josephus’s account, Abram’s Egyptian sojourn spread civilization to the South.