B. 1937. Studied at the Faculty of History of the University of Warsaw. 1959–1961: scholarship from Fondazione Giorgio Cini in Venice. Began his research at the Institute of History, University of Warsaw, from which he was dismissed for political reasons. Worked at the Institute of History of Material Culture, Polish Academy of Sciences. During the communist period in Poland – democratic opposition activist and co-founder of the Solidarity movement. Arrested and imprisoned several times for, among others, an open letter to the communist party and for trade union-related activities. Between 1989 and 1991 Senator of the Republic of Poland. Professor since 1990. 1992–1994: lecturer at the University of Wrocław. Since 1994 has worked at the Institute of History, University of Warsaw. Has also lectured at École des Hautes Études en Sciences Sociales and Collège de France in Paris, and the La Sapienza University of Rome. Author of numerous academic publications on medieval history which have won a number of prestigious awards.