The historical setting
The Sultan Ahmed Mosque (Sultanahmet Camii), popularly known as the Blue Mosque, is an Ottoman-era historical imperial mosque located in Istanbul, Turkey. It was constructed between 1609 and 1617 during the rule of Ahmed I. It attracts a large number of tourists and is one of the most iconic and popular monuments of Ottoman architecture. The mosque has a classical Ottoman layout with a central dome surrounded by four semi-domes over the prayer hall. It is fronted by a large courtyard and flanked by six minarets. On the inside, it is decorated with thousands of Iznik tiles and painted floral motifs in predominantly blue colours, which give the mosque its popular name.
The mosque's külliye (religious complex) includes Ahmed's tomb, a madrasa, and several other buildings in various states of preservation. The mosque was built next to the former Hippodrome and stands across from the Hagia Sophia, another popular tourist site.
Construction
After the Peace of Zsitvatorok, seen as a blow to Ottoman prestige, Sultan Ahmed I decided to build a large mosque in Istanbul in the hope of soliciting God's favour. He was the first sultan to build an imperial mosque since Selim II (d. 1574), as both Murad III and Mehmed III before him had not constructed their own. The mosque was built on the southeast side of the old Byzantine Hippodrome, near the Hagia Sophia, which had been converted into a mosque, that acted as a source of inspiration for the Ottoman architects, a site of great symbolic significance that allows it to dominate the city's skyline.
The mosque's location was originally occupied by the Hippodrome's bleachers and its imperial box (where the emperor sat when attending events here). During excavations in the early 20th century, some of the ancient seats were discovered in the mosque's courtyard. Given the mosque's location, size, and number of minarets, it is probable that Sultan Ahmed intended to create a monument that rivalled or surpassed the Hagia Sophia. Prior to construction, this site was occupied by the palaces of several Ottoman viziers, including Sokollu Mehmet Pasha and Güzel Ahmet Pasha, which required a costly expropriation process.
Layout and main features
The mosque's interior is dominated by its dome and cascading semi-domes. The main dome reaches a height of 43 metres (141 ft). The weight of the dome is supported by four massive cylindrical pillars. The transition between the central dome and the pillars is achieved by four long, smooth pendentives. Smaller pendentives are used for transitions between the semi-domes and their exedrae and between the hall's corner domes and the surrounding structure. The transitions between the smaller exedrae and the supporting walls or arches are covered by muqarnas (stalactite-like sculpting) made of stucco. By employing these elements, Mehmed Agha created a softer progression from the rectangular outer walls to the round central dome.
A two-floor gallery, supported on columns, runs along three sides of the prayer hall, except for the southeastern (or qibla) side, where the mihrab is located. Two fountains are incorporated into the two northern pillars of the mosque, similar to the Süleymaniye Mosque's prayer hall. The floors are covered with carpets, which are donated by the faithful and are regularly replaced as they wear out. At ground level, the focus of the prayer hall is the mihrab, which is made of finely carved marble, with a muqarnas niche and two inscription panels above it.
Minarets
On the outside, Mehmed Agha used the cascade of domes and semi-domes, combined with more curved and multi-tiered supported elements, to create a softer profile that builds up smoothly towards the summit of the central dome, much like he did with the interior. This approach differs slightly from that of Sinan and earlier Ottoman architects, who used the deliberate juxtaposition of curved domes and vertical elements to create a more dramatic effect. On the inside, the mosque courtyard has a classic rectangular peristyle form, lined on each side with an arcaded and domed portico (or riwaq). There are a total of 26 columns supporting the porticos and 30 domes above them.
Unlike the courtyards of the Süleymaniye Mosque and Selimiye Mosque designed by Sinan, where the portico in front of the prayer hall is taller than those on the other three sides, Mehmet Agha kept the arches of the southeast portico level almost with the others, thus prioritizing greater uniformity. A heavy iron chain hangs in the northwestern entrance (from the Hippodrome) to the outer precinct of the mosque. Only the sultan was allowed to enter the court of the mosque on horseback.