Bulk of the Greek texts that are available today (around 40,000 of 55,000) have been transmitted through Greek scholars of the Byzantine Empire. In 1453, when the Byzantine Empire fell to the forces of the Ottoman sultan Mehmed II, the Greek scholars fled to Western Europe with most of their texts, which must have contributed to the ongoing intellectual revolution (the Renaissance) happening in that part of Europe. In the area of intellectualism, the Byzantines were a success. Their failures are cultural and political. They wanted to be a great empire without fighting to defend their culture and the borders of their empire.
The idea of a “holy war” was abhorrent to the Byzantines. They believed that though a war might sometimes be necessary, it could never be holy—since killing was a sinful activity. Their political strategy was devoted to maintaining political power without having to fight wars. The crusaders could not have done anything to help the Byzantines, who were overconfident that they would keep prevailing in the region by the virtue of their intellectualism. The Byzantines thought that they could neutralize every foreign adversary through diplomacy and negotiations, and if military force had to be deployed, they could rely on mercenaries to do the dirty work of fighting. They expected the crusaders who arrived in the First Crusade to act as their mercenary troops and were appalled when they realized that the crusaders intended to free the holy land.
Despite their intellectualism, their knowledge of religion, culture, and history, the Byzantines could not develop a political and spiritual connection with the crusaders. During the time of the crusades, the intellectualism of the Byzantines had a rather negative impact—it prevented them from seeing the political reality that their Empire was doomed.