Despite the wealth of quantifiable material in the Florentine archives, historians have not in large numbers followed the path-breaking lead of Herlihy and Klapisch-Zuber in analyzing these archival materials from a statistical point of view. Exceptions include Cohn, Weissman, Molho, Litchfield, Barbagli, Padgett, McLean, Emigh, and Botticini.

Statistical methods remain invaluable tools, however, for answering a variety of historiographical questions, including the social-history ones in which Herlihy was

interested. What were the family structures in Renaissance Florence, for various categories of people? What were the logics of intermarriage among these families? How

much social mobility was there in Renaissance Florence? Did any of these change during

the Trecento and Quattrocento? Statistical methods are not the only procedures through

which questions such as these can be answered, but they provide a useful perspective, especially on aggregate patterns and trends. Herlihy and Klapisch-Zuber, along with the follow-up by Barbagli, posed their

questions and answers about family structure at the level of the household. In contrast, this article poses its similar questions and answers at the level of the lineage. The best current point of departure for this level of analysis is the study of Florentine marriage by Molho. In addition to providing a statistical overview of Florentine marriage patterns, Molho’s study usefully linked the two related topics of lineage intermarriage and political elite structure. Molho argued that stability both in Florentine lineages and in Florentine “ruling class” composition were caused by endogamous intermarriage, which recycled

substantial dowries among a relatively closed set of elite lineages, thereby buffering them

against the high elite-family extinction rates common in other countries in Europe.

The statistical results herein will support Molho’s conclusion about the importance of marriage for sustaining the resilience of Florentine lineages over perilous demographic time. But they will not support Molho’s conclusion about elite stability and

closure, at least for the two-century time period of this study. I shall document high rates

of relative social mobility among lineages on the dimensions of wealth and political

office, and high rates of social mobility during the Albizzi regime on the dimension of marriage itself.