Thus their months coincided with the Jewish months...

Thus their months coincided with the Jewish months; and Rajab coincided with Abib (i.e., Nisan) of the Jews. And the Jewish 7th month coincided with Muharram of the Arabs. (In original Hebrew reckoning, this seventh month was called Ethanim; now it is called Tishri I). As the original Jewish year began near the spring equinox (i.e. 21st March of the Gregorian calendar), the seventh month was bound to occur in SeptemberOctober.

Some time after the Exile, the Jews changed the new year from Nisan to the day of the new moon of the 7th month. Now it is their first month; except that the system of fasting and observing other laws concerning…