Muharram is the first month of the Islamic calendar. It is one of the four sacred months of the year in which fighting is prohibited. Since the Islamic calendar is lunar, Muharram moves from year to year when compared with the Gregorian calendar. Muharram is so called because it is unlawful to fight during this month, the word is derived from the word haram, meaning “forbidden”. It is held to be the most sacred of all the months, excluding Ramadan. Some Muslims fast during these days. The tenth day of Muharram is called Yaumu-l ‘Ashurah, which is known by Shia Muslims as ‘the day of grief’. On this day the death of Imam Huessein, grandson of Prophet Mohammad, is mourned. He was killed in the 7th century battle of Kerbala.