Ashura is the Islamic holy day that is observed on the 10th of the Islamic month of Muharram. Shi'ite Muslims regard it as a major festival marking the martyrdom of the Prophet's grandson, Hussein.
Ashura has been a day of fasting for Sunni Muslims since the days of the early Muslim community. It marks two historical events: the day Nuh (Noah) left the Ark, and the day that Musa (Moses) was saved from the Egyptians by Allah.
Shi'a Muslims, in particular, use the day to commemorate the martyrdom of Hussein, a grandson of the Prophet, in 680 CE.