The nature of medieval political entities in Mount Lebanon is still debatable. Meanwhile, toponymic evidence from contemporaneous primary sources suggests that the Mardaite fiefs, created around 680, continued to thrive under the Crusades, till 1305. The used method draws a map of medieval Mount Lebanon via a restitution of primary sources (Crusader, eastern Roman, and Arabic) to show the possible perimeters of the local Christian fiefs. Clearly, primary sources distinguished between the natural referent of Lebanon (the mountain chain) and the political one (Mardaite fiefs). An attentive restitution of post-Crusader sources (Ibn Qilaï’s of 1500 and Sionita’s of 1619, amongst others) allows us to a posteriori map of a medieval Mount Lebanon where the local ruling elite (mostly Maronite) considered itself as part of Chalcedonian Christendom, recognising the authority of the local Crusader political structures of Outremer, but also the political suzerainty of eastern Roman emperors.