The arts and sciences, too, were nowise promoted by the proper crusaders. The disorderly troops that first flocked to Palestine had not the least notion of them; and were not likely to acquire them in the suburbs of Constantinople, or from the Turks and mamelukes in Asia. In the succeeding campaigns we need not reflect on the short time the armies passed there, and the wretched circumstances under which this time was often spent merely on the confines of the country, to dissipate the splendid dream of great discoveries imported thence. The pendulum clock, which the emperor Frederick II received as a present from Kamil, did not introduce gnomonics into Europe; the Grecian palaces, which the crusaders admired in Constantinople, did not improve the style of European architecture. Some crusaders, particularly Frederick I and II, laboured to promote the progress of knowledge: but Frederick I did this ere he beheld Asia; and the short visit paid that country by Frederick II served only as a fresh stimulus to urge him forward in that course of government which he had long before chosen. Not one of the spiritual orders of knighthood introduced any new knowledge into Europe, or contributed to its cultivation.
All that can be said in favour of the Crusades, therefore, is confined to a few occasions, on which they co-operated with causes already existing, and involuntarily promoted them.
(1) As multitudes of wealthy vassals and knights repaired to the Holy Land in the first campaigns, and many of them never returned, their estates were of course sold or swallowed up by others. By this they profited who could, the liege lord, the church, the cities already established, each after his own manner: this promoted and accelerated the course of things, tending to confirm the regal power by the erection of a middle class, but was by no means its commencement.
(2) Men became acquainted with countries, people, religions, and constitutions of which they were before ignorant; their narrow sphere of vision was enlarged; they acquired new ideas, new impulses. Attention was drawn to things which would otherwise have been neglected; what had long existed in Europe was employed to better purpose; and as the world was found to be wider than had been supposed, curiosity was excited after a knowledge of its remotest parts. The mighty conquests made by Jenghiz Khan in the north and east of Asia attracted men’s eyes chiefly towards Tatary; whither Marco Polo the Venetian, Rubruquis (Guillaume de Rubrouck), the Frenchman, and John de Plano Carpino (Giovanni Piano Carpini), an Italian, travelled with very different views: the first, for the purpose of trade; the second, to satisfy royal curiosity; the third, sent by the pope, to make converts of the people. These travels, of course, have no connection with the Crusades, before and after which they were undertaken. The Levant itself is less known to us from these expeditions, than might have been expected: the accounts the Orientals give of it, even in the period when Syria swarmed with Christians, are still indispensable to us.
(3) Finally, in this holy theatre Europeans became better acquainted with one another, though not in a manner much to be prized. With this more intimate acquaintance kings and princes for the most part brought home an implacable enmity: in particular the wars between England and France derived from them fresh fuel. The unfortunate experiment, that a Christian republic could and might contend in unison against infidels, formed a precedent for similar wars in Europe, which have since extended to other quarters of the globe. At the same time it cannot be denied that, while the neighbouring powers of Europe obtained a closer inspection of their mutual weaknesses and strength, some obscure hints were given for a more comprehensive policy, and a new system of relationship in peace and war. Everyone was desirous of wealth, trade, conveniences, and luxuries; as an uncultivated mind is prone to admire these in strangers, and envy them in the hands of another. Few, who returned from the East, could be satisfied with European manners; even their heroism left much behind, awkwardly imitated Asia in the West, or longed for fresh travels and adventures. For the actual and permanent good produced by any event is always proportionate to its consonancy with reason.
Unfortunate would it have been for Europe if, at the time its military swarms were contending for the Holy Sepulchre in a corner of Syria, the arms of Jenghiz Khan had been sooner and more powerfully turned toward the West. Then probably our quarter of the globe would have been the prey of the Mongols, like Poland and Russia; and its nations might have dislodged, with the pilgrim’s staff in their hands, to tell their beads round the object of their contention.
GIBBON ON THE RESULTS OF THE CRUSADES