The Sipahsalar Mosque is a large congregational mosque and madrasa in Tehran. It is named after its patron, Mirza Husayn Khan Sipahsalar Qazvini, a chancellor of Nasir al-Din Shah Qajar. Historical written sources date the initial construction of the building to 1879/1296 AH, but construction continued until the early 1890s/1300s AH and beyond. After the Iranian Revolution, the mosque was renamed Masjid-i Shahid Mutahhari (Mosque of the Martyr Mutahhari). Part of the building now houses a high school (Madrasa-i 'Ali-i Shahid Mutahhar).The complex occupies an irregular plot of land at the intersection of two broad avenues, one running roughly north-south, and the other running roughly east-west. The exterior is made to align with these streets, while the interior is arranged around a central courtyard aligned with the qibla (southwest). The mosque lies just to the south of the site of the Baharistan palace and the old Iranian Parliament Building.The entrance portal takes the form of a monumental iwan with two minarets that opens onto the avenue on the complex's west side. From behind this iwan portal, a domed vestibule gives access to two hallways that eventually lead to the central courtyard, emerging on either side of an iwan on its northwestern facade. These hallways conform to the orientation of the central courtyard, and the domed vestibule serves as a transition point between the axis of the exterior facade and the axis of the interior courtyard and surrounding structures.The courtyard is a rectangular, quadrupartite garden (chahar-bagh), with a large circular pool at the center. Four paths intersect at this pool, and between them are the four garden plots. On each side of the courtyard is an iwan, the largest and most ornate being the one on the qibla side (southwest). The qibla iwan takes the form of a large pointed arch flanked on either side by two smaller arches surmounted by balconies. Two minarets flank the central arch, and two more minarets - slightly shorter in stature - rise from the outer ends of the two side arches. The iwan directly opposite the qibla (northeastern side) is also adorned with two minarets, rising to a shorter height, and a clock tower. Small arched niches covered by semi-domes line the walls between these iwans, giving onto dormitory chambers behind them for resident students of the mosque's madrasa.The qibla iwan gives onto a large, square hall, surmounted by a dome and flanked on three sides by covered bays. On the southwestern bay, an ornate mihrab marks the direction of prayer. The two side arches flanking the qibla iwan give onto smaller domed chambers. On the eastern side of the complex, behind the southeastern iwan, is a large covered hall used for prayer in the colder winter months. It is a rectangular space oriented northeast to southwest, and is composed of five rows of 12 domed bays supported by a total of forty-four columns. Three niches mark the direction of prayer on the southwestern wall of this covered hall.A corridor running from the eastern corner of the courtyard along the side of the covered prayer hall gives access to a smaller portal on the east side of the complex.Sources: Ḥājjī-Qāsimī, Kāmbīz, ed. Ganjnāmah-i farhang-i ās̲ār-i miʻmārī-i Islāmī-i Īrān, Vol. 3, pp. 100-111. Tehran: Dānishgāh-i Shahīd Bihishtī, 1996. “Mu‘arrafī-i kāmil-i Masjid-i Sipah’sālār (madrasah-yi ‘ālī-i Shahīd Muṭahharī)." Grūh-i mi‘marān-i Āril. https://www.arel.ir/fa/News-View-1147.html
