experience which had taught the Moslems to remain at a safe distance, or
to the perfidy of the Egyptian mariners, who deserted with their ships
to the emperor of the Christians. The trade and navigation of the
capital were restored; and the produce of the fisheries supplied the
wants, and even the luxury, of the inhabitants. But the calamities of
famine and disease were soon felt by the troops of Moslemah, and as the
former was miserably assuaged, so the latter was dreadfully propagated,
by the pernicious nutriment which hunger compelled them to extract from
the most unclean or unnatural food. The spirit of conquest, and even of
enthusiasm, was extinct: the Saracens could no longer struggle, beyond
their lines, either single or in small parties, without exposing
themselves to the merciless retaliation of the Thracian peasants.
An army of Bulgarians was attracted from the Danube by the gifts and
promises of Leo; and these savage auxiliaries made some atonement for
the evils which they had inflicted on the empire, by the defeat and
slaughter of twenty-two thousand Asiatics. A report was dexterously
scattered, that the Franks, the unknown nations of the Latin world, were
arming by sea and land in the defence of the Christian cause, and their
formidable aid was expected with far different sensations in the camp
and city. At length, after a siege of thirteen months, the hopeless
Moslemah received from the caliph the welcome permission of retreat.
* The march of the Arabian cavalry over the Hellespont and through the
provinces of Asia, was executed without delay or molestation; but an
army of their brethren had been cut in pieces on the side of Bithynia,
and the remains of the fleet were so repeatedly damaged by tempest and
fire, that only five galleys entered the port of Alexandria to relate
the tale of their various and almost incredible disasters.

In the two sieges, the deliverance of Constantinople may be chiefly
ascribed to the novelty, the terrors, and the real efficacy of the
_Greek fire_. The important secret of compounding and directing this
artificial flame was imparted by Callinicus, a native of Heliopolis
in Syria, who deserted from the service of the caliph to that of the
emperor. The skill of a chemist and engineer was equivalent to the
succor of fleets and armies; and this discovery or improvement of the
military art was fortunately reserved for the distressful period, when
the degenerate Romans of the East wer