In historical studies, prosopography is an investigation of the common characteristics of a historical group, whose individual biographies may be largely untraceable, by means of a collective study of their lives, in multiple career-line analysis. Prosopographical research has the goal of learning about patterns of relationships and activities through the study of collective biography; it collects and analyses statistically relevant quantities of biographical data about a well-defined group of individuals. This makes it a valuable technique for studying many pre-modern societies.
British historian Lawrence Stone (1919–1999) brought the term to general attention in an explanatory article in 1971. The word is drawn from the figure prosopoeia in classical rhetoric, introduced by Quintilian, in which an absent or imagined person is figured forth—the "face created" as the Greek suggests—in words, as if present.
Stone noted two uses of prosopography as a historians' tool: first, in uncovering deeper interests and connections beneath the superficial rhetoric of politics, in order to examine the structure of the political machine; and second, in analysing the changing roles in society of particular status groups—holders of offices, members of associations—and assessing social mobility through family origins and social connections of recruits to those offices or memberships. "Invented as a tool of political history," Stone observed, "it is now being increasingly employed by the social historians."
A certain mass of data is required for prosopography research. The collection of data underlies the creation of a prosopography and, in contemporary research, this is usually in the form of an electronic database. But, data assembly is not the goal of prosopographical research; rather, the objective is to understand patterns and relationships by analysing the data. A uniform set of criteria needs to be applied to the group in order to achieve meaningful results. And, as with any historical study, understanding the context of the lives studied is essential.
In the words of prosopographer Katharine Keats-Rohan, "prosopography is about what the analysis of the sum of data about many individuals can tell us about the different types of connection between them, and hence about how they operated within and upon the institutions—social, political, legal, economic, intellectual—of their time."
In this sense prosopography is clearly related to, but distinct from, both biography and genealogy. Whilst biography and prosopography overlap, and prosopography is interested in the details of individuals' lives, a prosopography is more than the plural of biography. A prosopography is not just any collection of biographies—the lives must have enough in common for relationships and connections to be uncovered. Genealogy, as practiced by family historians, has as its goal the reconstruction of familial relationships, and as such, well-conducted genealogical research may form the basis of a prosopography, but the goals of prosopographical research are generally wider.
The nature of prosopographical research has developed over time. In his 1971 essay, Lawrence Stone discussed an 'older' form of prosopography which was principally concerned with well-known social elites, many of whom were already well-known historical figures. Their genealogies were well-researched, and social webs and kinship linking could be traced, allowing a prosopography of a 'power elite' to emerge. Prominent examples which Stone drew upon were the work of Charles A. Beard and Sir Lewis Namier. Charles Beard's An Economic Interpretation of the Constitution of the United States (1913) offered an explanation of the form and content of the U.S. Constitution by looking at the class background and economic interests of the Founding Fathers. Sir Lewis Namier produced an equally influential study of the 18th century British House of Commons, and inspired a circle of historians whom Stone lightly termed "Namier Inc."
Stone contrasted this older prosopography with what in 1971 was the newer form of quantitative prosopography, which concern was with much wider populations including, particularly, "ordinary people". An example of this kind of work, published slightly later, is Emmanuel Le Roy Ladurie's pioneering work of microhistory, Montaillou: The Promised Land of Error (1978), which developed a picture of patterns of kinship and heresy, daily and seasonal routine, in a small Occitan village, the last pocket of Cathars, over a 30-year period from 1294 to 1324. Stone anticipated that this new form of prosopography would become dominant as part of a growing wave of Social Science History. But, prosopography and other associated forms of social science and quantitative history went into a period of decline during the 1980s. In the 1990s, however, perhaps because of developments in computing, and particularly in database software, prosopography was revived. The 'new prosopography' has since become clearly established as an important approach in historical research.
- Josie M. Abbott used prosopography to construct a group biography of women secretarial workers in the late 19th and early 20th centuries in The Angel in the Office (2009).
- Barbara Harvey's Living and Dying in England 1100–1540: The Monastic Experience (1993) is a prosopography that draws a group picture of monastic life, centred on the aggregate experience of the monks of Westminster Abbey. It explores some major themes of daily life: corporate and personal charity, diet, sickness and mortality, and servants. The mosaic is formed of insight into a multitude of obscure lives that can never be documented as individual biographies.
- Sociologist Michael Erben explored the use of prosopography to investigate what might be called a street biography in A Preliminary Prosopography of the Victorian Street (1996). Sourced mainly from census records, the data included not only demography but spatial classifications, occupations, and domestic arrangements of a street in Victorian Oxford. This material forms what Erben describes as an Unaffiliated or Disinterested Group, i.e. spatial locale may be all inhabitants had in common, unlike Intentional Groups, with explicit shared interests, found in more traditional prosopography. The work shows that such Unaffiliated Groups can yield much information on subjects such as social mobility in a given place and time.
- Debra Nails compiled a prosopography of Plato and other Socratics by exploring the biographies of each person mentioned in the Socratic literature to explore how Socrates interacted with others. Plato mentions many contemporaries of Socrates, from political figures to sophists, often using them as characters in the dialogues and foils for his criticism.
- Albion's Seed is a 1989 book by David Hackett Fischer that examines the details of the folkways of four groups of settlers from the British Isles who moved from distinct regions of Great Britain and Ireland to settle different regions of the American colonies, creating distinctly different cultures.
- Ronald Syme's influential The Roman Revolution (1939) is an important example of the prosopography of ancient Rome. It gathers meticulous detail on the lives of several prominent individuals important in the transition from the Roman Republic to the Roman Empire (i.e., the late 1st century BC). Syme's techniques and interpretations altered forever the understanding of this period.
- Friedrich Münzer (22 April 1868 - 20 October 1942) was a German classical scholar noted for the development of prosopography. He demonstrated through thousands of biographies of prominent Romans, that family relationships in ancient Rome were connected to political struggles.
- "multiple career-line analysis (as the social scientists call it)", Lawrence Stone remarked, in "Prosopography", Daedalus 100.1 (1971), pp 46–71.
- Lawrence Stone, "Prosopography", Daedalus 100.1 (1971), pp 46–71.
- Stone 1971:47.
- The classic early example of prosopography was the series of volumes of Prosopographia Imperii Romanae, edited by P. von Rohden and H. Dessau, (Berlin), appearing from 1897, which amassed a database covering the governing class of the Roman Principate.
- Keats-Rohan, Katharine. History and Computing. 12.1, p. 2
- Abbott, Josie M., The Angel in the Office. British Sociological Association, 2009.
- Carney, T. F. "Prosopography: Payoffs and Pitfalls" Phoenix 27.2 (Summer, 1973), pp. 156–179. Assessing results of prosopography applied to Roman Republican history.
- Erben, Michael, "A Preliminary Prosopography of the Victorian Street", Auto/Biography Vol 4, 2/3, 1996.
- Beech, George, "Prosopography" in Medieval studies: an introduction, ed. James M. Powell, Syracuse University Press, 1992.
- Keats-Rohan, Katherine S. B. (ed)., Prosopography Approaches and Applications: A Handbook. Oxford : Prosopographica et Genealogica, 2007.
- Lindgren, M., 'People of Pylos: Prosopographical and Methodological Studies in the Pylos Archives (Boreas). Uppsala (1973)
- Radner, K. (ed.), The Prosopography of the Neo-Assyrian Empire. Helsinki, 1998–2002. 
- Prosopography of the Later Roman Empire. Cambridge: University Press, 1971–92.
- Krummel, Donald W., "Early American Imprint Bibliography and its Stories: An Introductory Course in Bibliographical Civics", in "Libraries & Culture", 40, No. 3 (Summer, 2005), pp. 239-250.
- "Prosopography Research". Modern History Research Unit, University of Oxford. Retrieved 30 December 2015. – a prosopography portal that includes a short guide, a bibliography, and an international directory of current projects and researchers.
- Prosopography of Anglo-Saxon England – a project designed to provide a comprehensive biographical register of recorded inhabitants of Anglo-Saxon England (c. 450–1066), to be accessible in the form of a searchable on-line database, and intended to facilitate further research in many different aspects of Anglo-Saxon studies.
- Prosopography of the Byzantine World, an online database compiled from Byzantine sources from 1025–1150
- Eligivs – Anagrafica del personale di zecca – Prosopography of the mint officials (Italian).