Why is Mashhad considered Iran’s foremost religious center?

Mashhad is considered Iran’s foremost religious center primarily because it houses the shrine of Ali al-Rida, the eighth imam of Twelver Shi'ah Islam. It is the only shrine of an imam located within Iran, making it a site of immense spiritual significance that attracts tens of millions of Shi'i pilgrims annually from both Iran and around the world.12

The city's religious identity is deeply intertwined with its history; the name "Mashhad" literally translates to "place of martyrdom," referring to the burial of the imam in what was once the village of Sanabad. Beyond its spiritual role, the shrine complex operates a massive charitable trust, or waqf, which is one of the wealthiest and most influential institutions in the country. This religious prominence has historically established Mashhad as a powerful political and economic hub, serving as a stronghold for the clerical-bazaar nexus that has significantly shaped Iranian politics, including during and after the Islamic Revolution.21