Mashhad is the capital of the province of Khurasan and the second-largest city in Iran. Its full original name was Mashhad-i Riḍā (the Place of Riḍā’s Martyrdom), indicating that it is the locality where the eighth Shīʿī imam, 'Alī b. Mūsā al-Riḍā, was supposedly poisoned in 818 by al-Ma'mūn (r. 813–833), the Abbasid caliph. 'Alī’s shrine is the most important center of pilgrimage in Iran, and Khurasan is one of the country’s wealthiest provinces. Mashhad gained in importance after the Mongol destruction of Ṭūs and many other major cities in 1220. Gohars…