CONSTANTINOPLE  AND  CAIRO
Jerusalem, and he assured Pope Innocent that even a small
army would make its recovery certain. The Pope was en-
couraged by John's confidence, and even more by the
calculation from the Bible that Islam was now due to be
destroyed. At the end of 1215 he proclaimed that Europe
must devote itself for two years to the preparation of an
expedition to the East, and that anyone who sent arms or
anything useful for war to the Moslems or traded in any way
with the enemy was liable to excommunication. The Temple
and the Hospital had heard many such pronouncements and
had known them pass quite unheeded in a continent which
seemed to have lost all interest in the Holy Landj but they
were optimistic of the results of this appeal. For Frederick 11,
Emperor of Germany, had taken the cross, and he inspired
confidence. Frederick, however, was not to come to the East
for several years, and when he did set out on a Crusade his
most bitter foes were not the Moslems but the Templars and
Hospitallers.
While the Pope was unable to persuade Frederick to enlist
for the Fifth Crusade, the command of the Holy See was
obeyed by many of the nobles. Innocent had fixed June ist,
1217, for the departure of the great expedition, but before
that date many Crusaders had started for the East, and during
the summer thousands of men came to Acre from every
country in Christendom. An army of between thirty and
forty thousand was collected, and, as the Moslems were un-
prepared to meet a determined attack from a force of this size,
the Christians might have gained much land. The campaign
was started confidently by the Crusaders, who marched to the
assault of a fortress on Mount Tabor. No relief was sent to
the small Moslem garrison, and the Christians appeared
certain to succeed in their initial effort in the expedition.
Superstition, however, robbed them of victory. Part of the
wall of,the fortress collapsed, burying a number of the
besiegers beneath it, and panic spread among the Crusaders.