Matthew Frank Stevens studied at Pennsylvania State University and the University of Wales, Aberystwyth, completing his PhD in medieval social and economic history in 2005. He is now an Associate Professor of history at Swansea University. He has been an Ulam fellow of the Polish National Agency for Academic Exchange, at Nicolaus Copernicus University, Toru?, an Eileen Power fellow of the Economic History Society, at Oxford University, and a research officer at the Institute of Historical Research, University of London. He is the author of numerous academic articles and two monographs: Urban Assimilation in Post-Conquest Wales: Ethnicity, Gender and Economy in Ruthin, 1282-1348 (2010) and The Economy of Wales, 1067-1536 (2019).; Roman Czaja studied history at the Institute of History and Archives Sciences of Nicolaus Copernicus University, Toru?, completing his PhD. in the Department of Arts in 1991. He is now a Professor of history at NCU, holding the Chair of Medieval History and Auxiliary Sciences of History. A fellow of the Alexander von Humboldt Foundation at Humboldt Universitat and Freie Universitat in Berlin, in 2018 he was honoured by the University of Debrecen with the degree of Doctor Honoris Causa. He is author of over 250 research articles and of five books. In 2008 he published Grupy rz?dz?ce w miastach nadba?tyckich w ?redniowieczu (Ruling Groups in the Cities of the Baltic Zone in the Middle Ages) with Nicolaus Copernicus University Press.