Note 67 — Chapter II

Some historians make Musa arrive after the death of Walid; and some place the latter event a year later (715). The records of the period of the early Khalifs are so confused and contradictory that it is by no means easy always to ascertain the correct date of an event; the difficulty is considerably increased by the error into which some historians have fallen, of confounding the lunar year of the Mohammedans with the solar year of the Julian era. The common lunar year of the Hegira has 354 days; but the Mohammedans count, in a cyclus of 30 years, 11 leap years of 355 days (the 2nd, 5th, 7th, 10th, 13th, 16th, 18th, 21st, 24th, 25th and 29th years of the cyclus).