[Footnote 86: The date of the conquest of Antioch by the
Arabs is of some importance. By comparing the years of the
world in the chronography of Theophanes with the years of
the Hegira in the history of Elmacin, we shall determine,
that it was taken between January 23d and September 1st of
the year of Christ 638, (Pagi, Critica, in Baron. Annal.
tom. ii. p. 812, 813.) Al Wakidi (Ockley, vol. i. p. 314)
assigns that event to Tuesday, August 21st, an inconsistent
date; since Easter fell that year on April 5th, the 21st of
August must have been a Friday, (see the Tables of the Art
de Verifier les Dates.)]