The aim of this study, based on an in-depth study of coeval references, is the analysis of the crossing of the Crusade legions, in 1096, through the Hungarian Reign to the borders of the Byzantine Empire. The Hungarian Reign, when the crossing studied occurred, was governed by Coloman I, who had recently gained power a few months before. Taking into account the following events of the Crusade, we focus on the Lorraine Legion, headed by the duke of Lower Lorraine, Godefroy de Bouillon and the diplomatic relations that developed between the French-Flemish noble élite and the Hungarian Court. The “Call” for the Crusade by Pope Urban II at Clermont in 1095, created great enthusiasm all over Christian Europe. This caused not only unorganized masses to react positively, but also many feudal armies to move towards Palestine. The scope of the Crusade movement, besides supporting Byzantium against the Turks, was mainly the setting-free of the Holy Sepulchre of Christ and of the Holy City of Jerusalem, under Islamic domination from the 7th century. Among the many possible paths to travel, many Crusaders made use of the overland path, across the Balkans. This path, which used the Route of the Roman Danubian Limes, had been abandoned centuries before due to the many invasions which had occurred on the peninsula between the end of the 4th century and the 10th century. The entrance in the orbit of Christianity of the Reign of Hungary and the conquest of the Bulgarian Reign achieved by Emperor Basilius II at the beginning of the 11th century had reopened the doors of this important route to Western Countries.