Muharram is the first month of the Islamic calendar. It is one of the four sacred months of the year in which fighting is not allowed. The other months are Dhu al-Qi'dah, Dhu al-Hijjah and Rajab. Since the Islamic calendar is a lunar calendar, Muharram moves from year to year when compared with the Gregorian calendar.
Muharram is held to be the most sacred of all the months, except for Ramadan. Some Muslims fast during these days. The tenth day of Muharram is the Day of Ashura. To Shia Muslims it is part of the Mourning of Muharram. The mourning is for Husayn ibn Ali who was the grandson of Prophet Muhammad and their third Imam.
Many Sunni Muslims fast during this day. It is in the hadith that Musa (Moses) and his people had a victory over the Egyptian Pharaoh on the 10th day of Muharram. The Islamic prophet Muhammad asked Muslims to fast on this day, and also a day extra either before or after. Many Muslims cook something sweet like sweet rice and share with their family and circle of friends to eat when breaking their fast.