The Eighth Crusade never reached major battle: an epidemic, understood at the time as dysentery, swept the crusader camp outside Tunis and killed Louis IX along with a substantial part of his army's leadership, and the historiography describes that outbreak narratively without estimating how many died from it.
What would resolve this A historian's or epidemiologist's estimate of deaths in the crusader camp outside Tunis during the 1270 outbreak, distinguishing disease deaths from the campaign's minimal combat losses.
OpenCrusading history, historical epidemiology.Christopher Tyerman, God's War: A New History of the Crusades