Every year, Shia Muslims from Iran and many other countries celebrate the birthday anniversary of their Eighth Imam, Ali bin Mousa al-Reza (PBUH), in his Holy Shrine in Mashhad and other parts of the world.

Imam Ali ibn Musa al-Reza (PBUH), the eighth Shi'ite Holy Imam was born on 11th Zee al-Qa'adah 148 A.H. in the holy city of Madinah. He was divinely entitled 'Al-Reza"(meaning that Allah Almighty and His Holy Messenger (PBUH) were deeply pleased with him). The Holy Imam (PBUH) is also considered as the Aalim (the Greatest Erudite) of the Holy Ahlul Bayt (PBUH).

On the 11th of Zil-Qa’dah in the year 148 AH, less than a month after the martyrdom of the Prophet’s 6th infallible successor, Imam Ja’far Sadiq (PBUH), when the bewildered assassin Mansour Dawaniqi was still trying to figure out who actually was the heir of his venerable victim, so as to do him harm as well, an enlightened heir was born to the still publicly unannounced heir of the deceased Imam. Little did the Abbasid usurper Mansour – one of the principal hijackers and deviators of the pro-Ahl al-Bayt uprising of the people of Khorasan – realize that the new addition to his victim’s family that year would soon transform not only Khorasan but the whole of Iran and the greater part of his own capital Baghdad in Iraq, into the realm of the devotees of the Prophet’s pure progeny, whom he thought had been totally deprived of their rights. Fifty-three years later in 201 AH, as the rotten bones of Mansour and his four tyrannical successors – Mahdi Abbasi, Hadi Abbasi, Haroun and Amin – rattled in their infernal graves, the son born in 148 AH to Imam Musa al-Kazem (PBUH) – the son and hitherto unannounced successor of Imam Sadeq (PBUH) – would step on the soil of Khorasan to establish a permanent foothold for the followers of the Prophet's Ahl al-Bayt.