There are many sources that allowed scholars to study the nature and functions of polygamous marriages of the Nahua nobility. Very few studies, however, focus on the marital relations of the Nahua commoners. This article presents exploratory research into various kinds of marriages of the macehualtin—polygamy, sororate, and levirate. Based on the available material (early censuses, inquisitorial records, sixteenth-century accounts) it discusses the functions that these types of unions played in Nahua society. Moreover, it reflects on the effects that the Christianization and prohibition of such marriages had on Nahua society. The Nahuas could either reshape their communities, by adjusting to the new rules, or continue their precolonial practices in hiding. Either way, the imposed Christianization can be analyzed through the notion of the cultural trauma, which occurred when the Nahuas were forced to reshape their communities to adjust to the new rules.