Lal Darwaza Masjid or the Ruby Gate Mosque is situated on the outskirts of the city of Jaunpur. It was built by Bibi Rajni, the queen of Sultan Mahmud Sharqi in 1447 and was dedicated to Maulana Sayyid Ali Dawood Kutubuddin, a Muslim saint of Jaunpur. The mosque was built specially for the Begum to serve as her private prayer hall.
The architectural style and design of the mosque substantially resembles Atala Masjid, though it is smaller in size as compared with the latter. It can be entered through three gates situated in the north, east and south of the monument.
Its eastern gate is built of red sandstone. Moreover, the mosque is situated adjacent to the Lal Darwaza or the Ruby Gate of the royal palace of Queen Bibi Rajye. This explains how the mosque got its name.
A large part of the construction material of Lal Darwaza Masjid was appropriated from the Hindu palaces, temples and other monuments that were destroyed by the Muslim fanatics.