European contact resulted in a devastating smallpox epidemic among the Mohawk in 1635; this reduced their population by 63%, from 7,740 to 2,830, as they had no immunity to the new disease. By 1642 they had regrouped from four into three villages, recorded by Catholic missionary priest Isaac Jogues in 1642 as Ossernenon, Andagaron, and Tionontoguen, all along the south side of the Mohawk River from east to west. These were recorded by speakers of other languages with different spellings, and historians have struggled to reconcile various accounts, as well as to align them with archeological studies of the areas. For instance, Johannes Megapolensis, a Dutch minister, recorded the spelling of the same three villages as Asserué, Banagiro, and Thenondiogo. Late 20th-century archeological studies have determined that Ossernenon was located about 9 miles west of the current city of Auriesville; the two were mistakenly conflated by a tradition that developed in the late 19th century in the Catholic Church.