December derived its name from the Latin word “Decem” meaning ten (10). According to the old Roman calendar, it was the 10th month. This was before they dedicated their new first month to January moving December to the position of being the 12th month though it maintained its name as the 10th month. According to the Biblical calendar, 1st of Kislev 5778 began on the 19th November 2017. The 30th of Kislev 5778 is December 18, 2017. The 1st of Tevet 5778 is December 19, 2017.