 Archaeologists have found human remains from the Japanese Paleolithic period, which have been carbon dated to more than 10,000 BC along with the bones of Naumann elephants.Numerous remains from the Jōmon period, and especially from the Yayoi and Kofun periods have also been found, including many kofun burial mounds.During the Nara period, the area was assigned to Atsumi, Hoi and Yana Districts of Mikawa Province and prospered during subsequent periods as a post town on an important river crossing of the Tōkaidō connecting the capital with the eastern provinces.