Prof. Karol Modzelewski (born 1937), Corresponding Member of the Polish Academy of Sciences, a medievalist.

Between 1962 and 1964, he was a doctoral student at the Institute of History of Warsaw University, from which he was expelled for political reasons by the decision of the Ministry. Between 1957 and 1964, he was a member of the Polish United Workers' Party (PZPR). In the years 1965-1967, 1968-1971 and 1981-1984, he was imprisoned for his political activity. Between 1972-1983, Prof. Modzelewski worked at the Institute of the History of Material Culture of the Polish Academy of Sciences, where he pursued his scientific career earning a Ph.D. degree in 1974 and qualifying as an assistant professor in 1978.

Between 1980 and 1981, he was a member of the regional and national governing body of NSZZ Solidarność. Since 31 March 1981, he was the spokesman of the National Liaison Commission, and in October 1981 he joined the National Commission appointed during the first convention of Solidarność. In the years 1987-1992, he worked at the Institute of History of the Polish Academy of Sciences - first as an assistant professor, and than as a professor. In the 1989-1991 period, he was a senator. After the self-dissolution of the Parliament, he continued his scientific activities at the Institute of History. In the years 1992-1994, he worked as an associate professor at the Institute of History of the Wrocław University, and since 1994 - as a full professor at the Institute of History of the Warsaw University, where between 2002 and 2004 he headed the Faculty of Medieval History.

Prof. Modzelewski has lectured as a visiting professor at the École Pratique des Hautes Etudes en Sciences Sociales in Paris and College de France, as well as at the "La Sapienza" University in Rome.

He is an author of 65 works on medieval history, including 3 books: Organizacja gospodarcza państwa piastowskiego (Economic Organization of the Piast State), Chłopi w monarchii wczesnopiastowskiej (Peasants in the Early Piast Monarchy), Barbarzyńska Europa (Barbarous Europe). He is a member of the Warsaw Learned Society and the Académie Européenne des Sciences, des Arts et des Lettres (Paris). In 1998, Prof. Modzelewski was awarded with the Order of the White Eagle.