We are now in a position to understand the complex nature
of the motives which animated the preachers, the generals, and the soldiers of
the Crusades; for these enterprises are a continuation on a greater scale of the
German, Spanish, and Norman wars of conquest.
Like the wars of Spain, the Crusades were suggested by
fears of a Mohammedan advance; the signal for the First Crusade was given by
the successes of the Seljuk Turks under Alp Arslan and Malik Shah (1071-1092).
These uncivilised and fanatical usurpers of the caliphate of Bagdad overran the
whole of Asia Minor and of Syria in twenty years; they dealt a heavy blow to
the Eastern Empire on the field of Manzikert (1071), and founded in Asia Minor
the sultanate of Roum; they established smaller principalities in Syria.
The
rulers of Constantinople sent urgent appeals for help to the West; and pilgrims
returning from the Holy Places complained loudly of the insults and persecutions
by which the conquerors manifested their hostility to the Christian faith.
Gregory VII, immediately after his election, was moved to plan an expedition
for the defence of the Eastern Empire, which he justly regarded as the bulwark
of Europe against Islam. He issued a general appeal to the princes of Europe
for help and personal service; he even proposed to accompany the relieving
force. But Gregory, though not without imagination, lacked the power of firing
popular enthusiasm, and aroused mistrust by the admission that he intended
using the Crusade in the first instance against the Normans of Lower Italy.
