This is an expansion of the Historica Arcanum bundle from Metis Publishing, released last year, a very well-researched fantasy middle-East setting from a group of Turkish authors and historians who really know the region and its history. This one covers the Crusades, and should have a different perspective to the usual westernized view of these wars. You will probably need the Historica Arcanum rules (from the previous bundle or available from the usual sources), which are a greatly modified version of D&D 5E.
https://bundleofholding.com/presents/ArcanumCrusades