One of the five canonical astronomy schools of 505 CE India is called Romaka — "the Roman." Varāhamihira's Pañcasiddhāntikā ranks it among the top three for accuracy, and its parameters give the game away: a calendar cycle of 2,850 years — exactly 150 Greek Metonic cycles of 19 years — with days reckoned from sunset at Yavanapura: Alexandria. Indian astronomers didn't hide their Greco-Roman sources; they cited them, tested them, and ranked them.