The Nahua (Aztecs) of ancient Mexico lived in large, extended family households (calli). A fundamental tenet of family history is that in the past high mortality was a major obstacle to household complexity. This was not the case for the Nahua, whose life expectancy was probably worse than any seen in Europe since the Black Death. Nahua populations were characterized by patriarchy, child marriage and greater proportions of complex and more diverse households than in regions of Europe which historians have identified as containing many complex households. Among the Nahua, although relationships within the household could be either uxorilocal or virilocal (relationship through the wife or the husband), subordination of women to male patriarchs was extensive. Most girls were married (cohabiting) well before the age of puberty. Thus, childless couples were common, but males without children rarely attained headship. While neither polygamy nor abandonment was widespread, their significance for gender oppression should not be denied. Widow-hood offered new opportunities for companionship, but only for widowers. For widows, remarriage was infrequent and subordination to a male relative was inevitable. In modern Mexico, few remnants of this pre-conquest household system remain. According to the 1990 census, fewer than 10 per cent of Mexicans live as extended kin or as non-relatives in a household, even in rural Morelos where four centuries ago the compound family was the norm. The few modern examples of multiple family households tend to be Hispanic-like virilocal, patrilineal extended families.