Marie secondly married at some time between September 1240 and 15 December 1241, Mathieu de Montmorency, Seigneur d'Attichy, who was killed in battle at Mansurrah on 8 February 1250 during the Seventh Crusade, led by King Louis IX of France.
Pollock, M. A. (2015). Scotland, England and France After the Loss of Normandy, 1204-1296: "Auld Amitie". The Boydell Press.
Rosenberg, Samuel N.; Pippenger, Randall T., eds. (2022). Tales of a Minstrel of Reims in the Thirteenth Century. The Catholic University of America Press.
Shadis, Miriam (2009). Berenguela of Castile (1180-1246) and Political Women in the High Middle Ages. Palgrave Macmillan.