The mosques in the citadel of Yerevan are lost today and almost unknown. Here, the most significant of them is reconstructed from visual and literary sources, documented by unpublished photographs, and related to the early Qajar period under the last Iranian governor Husayn Khān, prior to the Russian conquest of Yerevan in 1827. The second mosque in the citadel is attributed to the Ottoman period; the third one remains uncertain. While the type of the Qajar mosque is compared to earlier buildings in Yerevan, notably the 18th-century Gök Jāmi', stylistic elements are analysed with reference to early 19th-century architecture in Iran and a building at Qazvīn. The interpretation seeks to understand the different references of the Qajar mosque as the construction of a visual statement of local and Iranian identity in a period of change.