How did Tehran develop from a village north of Ray into a major city?

Tehran originated as a small village north of Ray, a major historical city that declined following the Mongol invasion of 1220. By the 13th century, Tehran had emerged as a prosperous market town known for its underground dwellings and gardens.12

Its strategic location at the foot of the Alborz Mountains and along the Silk Road facilitated its growth. In 1554, the Safavid ruler Ṭahmāsp I fortified the town with walls and a bazaar, transitioning it into a garrison town and regional center.32

Tehran’s status as a major capital was cemented in 1786 when Agha Mohammad Khan, founder of the Qajar dynasty, selected it as his seat of power due to its proximity to his tribal territories. The city expanded rapidly as it became an administrative hub, attracting soldiers and courtiers. By the late 19th century, extensive modernization programs further enlarged the city, creating new infrastructure and a distinct urban structure that defined its character as a modern capital.4