This thesis focuses on Jesuit missions to the Seneca Iroquois, which spanned from 1668-1709. Using museum collections of archaeological artifacts and historical sources, the goal of my research is threefold: to update the data on Christian-themed artifacts found at Seneca sites, to develop a more cohesive portrait of Iroquoian spirituality, and to examine whether the material and historical records present a case for religious syncretism. My updated enumeration of Jesuit-style finger rings takes into consideration current excavations, and has more than doubled since Alice Wood's 1974 study. By contrast, the religious medals, crosses and crucifixes found on Seneca territory have never been analyzed until now. Research on the religious medals was aided by the Clark Manuscript, compiled from 1894-1902 by General John S. Clark (1823-1912). Overall, my research decisively concludes that Christian-themed artifacts occur both within and outside of the Jesuit missionary period.