According to Shi’a belief, God never leaves the earth without His deputy, the ultimatum, and infallible Imam. After the martyrdom of the eleventh Imam (a) in 260/864, the twelfth Imam, Muhammad b. al-Hasan al-’Askari (a), who was born in 255/646, inherited the position. By God’s knowledge and will, the twelfth Imam disappeared from sight in 260/874, although he is still alive and shall reappear one day to free the world from the violence and injustice that fills it, in order to place justice and fairness instead.