Martyrdom of Imam Hasan Al-Askari (a)
Imam Hasan Al-Askari (a) spent his short life in sufferings and distresses. The Abbasid kings spared no effort in oppressing him. They moved him from a prison to another. 
They subjected him to confinement and imposed on him an economical blockade. They prevented him from meeting with his followers as they
Imam Reza (A.S.) and Regency to Caliphate
We are in front of an important historical event which busied the public opinion and stunned all political circles. The event is that al-Ma’mun appointed Imam al-Rida, peace be on him, as a heir apparent after him; it indicates that the succession would be taken from the ‘Abbasids and handed over to their opponents, the ‘Alawides; it astonished the people and they asked each other:
The Last Hours of the Holy Prophet (S.A.W.)
The Holy Prophet (S) returned from the Farewell Haj at the end of the month of Zilhaj of 10 A.H. After passing the one month of Muharram, he fell ill at the beginning of Safar 11 A.H.