The Martyrdom of Imam Ali, observed on the 21st day of Ramadan, commemorates the death of Ali ibn Abi Talib, who was the son-in-law of the Prophet Muhammad. This year, it takes place on April 12. Did you know that he is one of the important personalities in Islam? Yes, he was considered to be the first Imam by Shia Muslims and was also the first male to accept Islam — this also makes him the first Muslim.