Both sociology and modern historiography had their origin in 19th century. The latter established the concept of historical periods and thus bequeathed to historiography theoretical ideas and concerns which were entirely absent from the work of earlier narrative historians and chroniclers. It bequeathed to modern sociology the notion of historical types of society and thus enabled the socialists to build classification of societies.
The interaction between two disciplines can be found in their subject matter. Subject matter of sociology and history overlap to a considerable extent. The historian frequently provides the material which sociologist uses.Infact historical sociology depends upon the data which only a historian can supply. Even comparative method often requires historical data. But the dependence is two fold. Sociological research also provides the information which the historian's need.Infact the subject matter of social history overlaps to a very great extent with sociology in general and historical sociology in particular. There is evidence of cooperation by sociologists and social historians. Historian's account of social structure of 19th century towns and of the characteristics of the medieval peasantry or the 18th century nobility and sociologist's study of social history of a variety of professions. There is a point of difference between the two. Radcliffe- Brown provided a clear-cut though simplistic answer. According to him 'Sociology is nomothetic, while history is idiographic'. The historian describes unique events, while the sociologist derives generalizations.
Indeed, there are generalizations in history too, but a sociologist analyses sociological data with the help of generalizations. In other words, the historian examines particular sequences of events; whereas a sociologist tests a generalization by examining the sequence of events. To word this particular difference between history and sociology in a very simple language: the historian is concerned with the inter-play between personality and social forces; whereas, the sociologist is largely concerned with the social forces themselves. History is primarily concerned with the past and essentially tries to account for the change over time while the main focus of sociology continues to be to search for recruitment patterns and to build generalizations. However given such works like Weber's Protestant Ethic and Spirit of Capitalism and Pitrin Sorokin's Social and Cultural Dynamics, the line for demarcation between history and sociology is becoming increasingly blurred. Yet H.R Trevor-Roper has tried to make a weak distinction by stating that historian is concerned with the interplay between personality and massive social forces and that the sociologist is largely concerned with these social forces themselves. However it is becoming increasingly clear that historiography and sociology cannot be radically separated. They deal with the same subject -matter viz men living in societies sometimes from the same point of view and the trends that the two shall continue to borrow from each other extensively.