December 12th is Rabi' al-awwal

Rabi' al-awwal (ربيع الأوّل) is the third month in the Islamic calendar. During this month, majority of the Muslims celebrate Mawlid - the birthday of the Islamic prophet Muhammad. Sunni Muslims believe the exact date of birth of Muhammad to have been on the twelfth of this month, whereas Shi'a Muslims believe him to have been born on the dawn of the seventeenth day. The name Rabī‘ al-awwal means the first [month] or beginning of spring, referring to its position in the pre-Islamic Arabian calendar. Hence this is considered to be a very blessed month.