Nuruosmaniye Mosque is the first to be constructed in the Baroque style in Istanbul. The mosque was completed under the name of ‘Nur-u Osmani’ during the era of Osman III, following the death of his brother Mahmud I. It was built by Mustafa Aga and his assistant Simeon Kalfa (Master Builder Simeon) between 1749 and 1755.
The mosque and its social complex, which were constructed during a period of Westernization influence on architecture, are considered a milestone in Ottoman architecture. In addition to the mosque, a social complex consisting of a madrasa, an imarethane (soup kitchen), a library, a tomb, a fountain, and a sebil (public fountain) was constructed. The social complex also includes some shops in its surroundings. The influence of the Baroque style can also be seen in the library, the tomb, the fountain, and the sebil (public fountain).
There are tall stairs on two sides in order to reach the mosque. The outer courtyard of the mosque, which was built on a square plan, is covered by a single dome.
The arcade passages on both sides lead to the entrance of the harem (area reserved for prayer). The main dome of the mosque has a diameter of 26 meters. The mosque is illuminated by 174 windows arranged in five rows. The protruding mihrab is polygonal and different from the mihrabs in classical Ottoman mosques. It is covered with a half-dome.
The Hünkar Mahfili (area reserved for the Sultan to perform his prayers) is located at the end of the eastern corridor. The two minarets adjacent to the building have two galleries and stone cones. The crescent was made of stone instead of lead for the first time in this mosque. The courtyard of the mosque has arcades and a polygonal structure, which makes it unique in Ottoman architecture. The mosque does not have a şadırvan, but it has designated ablution areas in the front and back. To the south of the mosque, the madrasa and imaret stand next to each other. The madrasa is the last of the sultan’s madrasas. Inside the tomb, there are the coffins of Şehsuvar Sultan and some şehzades. The two-story library is considered one of the unique examples of Baroque design. The upper floor functions as a library, while the ground floor is a storage area. Nuruosmaniye Sebil (public fountain) is a marble structure. It covers the circular main area and the rectangular area next to it.