Medieval Marriage Characteristics: A Neglected Factor in the History of Medieval Serfdom Only recently have historians come to appreciate the role which demographic factors have played in the social history of the Middle Ages. In the traditional view, medieval society remained rigidly stratified and static; change, when it came, was attributable largely to external factors playing upon the medieval world-the opening of frontiers, the expansion of trade, and the growth of towns. All of this is true, but it does not represent a complete picture of the forces working to transform medieval society. This paper examines another factor, hitherto neglected by scholars, which apparently played a major role in the social history of the Middle Ages, and, particularly, in the history of medieval serfdom: the marriage patterns characteristic of the servile population. I have utilized one of the magnificent documents of medieval social history-the Polyptych of the Abbot Irminon, redacted probably between c. 8oi and c. 820. It describes the lands and the some 2,000 families belonging to the monastry of Saint Germain-des-Pres near Paris. This polyptych of Saint Germain-des-Pres is an extraordinary example of the medieval censier or manorial extent of the estates and benefices which comprised and/or were dependent upon an abbey or church. There is a breve, or chapter, describing each part of the seigneury, relating in some detail the type and size of the elements of the demesne, the amount of arable tenanted land, the number of people on the land, the dues they owed, and information on mills and churches. The polyptych has been the worthy object of intense and careful study for over a century. The manuscript, which is preserved in the Bibliotheque Nationale (Fonds latin, manuscript no. I2832), has been edited twice. The first edition (1844) was by Guerard, whose detailed introduction has become a starting point for all studies of the document.' Fifty years later Longnon revised some of Guerard's paleographic interpretations and reduced the introduction to more manageable