Henri Pirenne

Henri Pirenne (December 23, 1862 in Verviers – October 25, 1935 in Uccle) was a Belgian historian and academic. Pirenne is considered as one of the most important historians of Belgium.
Biography.
He studied at the University of Liège and was a professor at the University of Ghent. His focus was on Medieval history, the history of Belgium and economic history.
He developed the so-called "Pirenne thesis" (nowadays out of date) in his book "Mohammed and Charlemagne" (published after his death in 1937). According to this opinion Mediterranean economics were disturbed by the early Islamic conquests and not by the barbarian invasions some centuries before.
Pirenne resisted the Dutchification of the University of Ghent. When this university had completely become Dutch-language spoken in 1930, he moved to the Brussels region where died in 1935, aged 72.