Hans (or Johannes A.) Mol, 1954, studied history and historical geography at the Vrije Universiteit Amsterdam. He obtained his doctorate there in 1991 with a thesis on the Frisian houses of the Teutonic Order. Since 1986 he has been working at the Fryske Akademy in Leeuwarden as a researcher in medieval history. Furthermore, he was affiliated with Leiden University as extraordinarius professor of history of the Frisian lands in the Middle Ages (2003-2020). He publishes about church and society, the military orders, warfare and the history of settlements and reclamations. He is also involved in the development of a historical GIS for the Northern Netherlands, based on the Napoleonic cadastre 1811-1832.