Suleymaniye Mosque, also known as Süleymaniye Mosque in Turkish, is a landmark monument in Istanbul, Turkey, located on the third hill of the city. Until 2019, it was the largest mosque in Istanbul, although it has now been surpassed by the Çamlıca Mosque. Even so, it remains one of the most recognizable sights in the city.

Built by order of Sultan Suleiman I, also known as Suleiman the Magnificent, the mosque was designed by the imperial architect Mimar Sinan, who was of Armenian/Greek descent or Turkish Orthodox. Construction work began in 1550 on the site of the former Eski Saray Palace and was completed in 1557.

Sinan's architectural design contrasted with that of the iconic Hagia Sophia, incorporating a symmetry and simplicity that highlighted its unique style. It is believed that Sinan was inspired by Italian architectural ideas, seeking symmetrical lines and rational forms.

The mosque suffered damage over the years, including fires and earthquakes, but has been restored several times. In the 19th century, the brothers Gaspare and Giuseppe Fossati restored it in the Ottoman Baroque style. However, a more recent restoration returned the structure to its original design.

The mosque's architecture is notable for its monumental courtyard and four minarets, symbolizing the importance of the sultan. The dome, with a height of 53 meters and a diameter of 26.5 meters, was once the largest in the Ottoman Empire in terms of base.

The interior of the mosque is equally impressive, with a spacious layout and subtle decoration, highlighting the restrained use of Iznik tiles and woodwork. In addition to the mosque itself, the complex includes a hospital, schools, baths, a public kitchen and other religious and cultural buildings.

On the grounds of the mosque are also several mausoleums, where important historical figures such as Suleiman I, his wife Roxelana and other sultans are buried. Sinan, the architect, is also buried nearby.

The Suleiman Mosque is an impressive testimony to the architectural and cultural splendor of the Ottoman Empire, and remains a place of historical and spiritual importance in Istanbul.