Sepahsalar Mosque and Seminary were the first and the greatest mosque and higher education school in Tehran whose design is a combination of Iranian architecture and the architecture used in Istanbul mosques. In general, the design of this building is inspired by Isfahan Jameh Mosque and Isfahan Chahar Bagh School and Hagia Sophia Mosque in Istanbul.
Mirza Hossein Khan Sepahsalar ordered in 1296 hijri year to build a mosque which is now one of the most elegant buildings in Tehran. Momtahen al-Dowleh designed it and Haj Hassan Ghomi was the architect.
The other aspect that magnifies the significance of this mosque is its library. There is now a treasury of more than 4200 manuscripts by compilers and about 10 thousand lithographic books in the library.
The building was registered in the list of national monuments in 1315 with registration number 260.