All Abrahamic religions believe in an end-times savior. All Abrahamic religions believe that someone will emerge who will save the world from the morass of oppression and cruelty. In Islam, the name of this savior has been mentioned. All Islamic denominations refer to this divine person and this great and extraordinary individual as Mahdi. Perhaps, there is no Islamic denomination that does not believe Mahdi (a.s.) will emerge. He is a descendent of the Holy Prophet (s.w.a.). Islamic denominations have even specified the name and epithet of that noble man. The feature of Shia ideology is that it thoroughly and clearly introduces this personality. It considers him as the son of the eleventh Imam – Imam Hassan al-Askari (a.s.). From the viewpoint of Shia historians and writers, his birth date is completely clear. Most of other Islamic denominations have not specified his birth date or they have not accepted it, but the Shia prove the existence and birth date of that great personality with strong and cogent reasons. Some people have dismissed the possibility of the existence and survival of a person over this long time. This is the only question that opponents have raised regarding Imam Mahdi (a.s.). However, the Holy Quran dispels this doubt with its clear words. The Holy Prophet (s.w.a.) says about Prophet Noah, “We sent Noah to his people, and he tarried among them a thousand years less fifty” [The Holy Quran, 29: 14]. This does not mean that he lived for 950 years. It apparently means that his mission – to invite people to God – lasted for 950 years. Therefore, this questioning is groundless.