Birthday of Ali ibn Abi Talib is observed by Muslims on the 13th day of the month of Rajab.
It is an official public holiday in Iran.
Ali ibn Abi Talib was the cousin of the Islamic prophet Muhammad and the husband of his daughter Fatimah.
Ali was also the first male to accept Islam.
He is considered the fourth and final of the Rashidun Caliphs by Sunni Muslims while Shia Muslims regard him as the first Imam after Muhammad.
Shias believe Ali and his descendants to be the rightful successors to Muhammad.
Ali is considered a tragic figure in Islamic history.
He took part in almost all the battles fought by the nascent Muslim community.
During his reign as appointed Caliph he encountered defiance and civil war.
He was murdered while praying in Masjid al-Kufa (the Great Mosque of Kufa) in 661.
Muslims respect Ali for his deep loyalty to the prophet Muhammad, passionate devotion to Islam, honesty, belief, knowledge, and courage.
He treated all Muslims equally and was generous in forgiving his defeated enemies.
Shia Muslims consider Ali to be the most important figure after Muhammad.
As Shia Islam is considered the official state religion in Iran, the birthday of Ali ibn Abi Talib is an official public holiday in this country.