Ottoman decoration
Decoration in Ottoman architecture takes on several forms, the most prominent of which include tile decoration, painted decoration, and stone carving. Beginning in the 14th century, early Ottoman decoration was largely a continuation of earlier Seljuk styles in Anatolia as well as other predominant styles of decoration found in Islamic art and architecture at the time. Over the course of the next few centuries, a distinctive Ottoman repertoire of motifs evolved, mostly floral motifs, such as rumî, hatayî, and saz styles. Calligraphic inscriptions, most characteristically in a thuluth script, were also a mainstay. From the 18th century onward, this repertoire became increasingly influenced by Western European art and architecture and went as far as directly borrowing techniques and styles from the latter.
File:Rüstem Pasha Mosque mihrab DSCF2405.jpg|thumb|Mihrab of the Rüstem Pasha Mosque, showing typical 16th-century decoration. The walls are covered with Iznik tiles at the beginning of their richest artistic phase, while in the center is a stone-carved muqarnas hood.
Ottoman tiles attained a prominent role in decoration. Starting in the early 15th century, cuerda seca tiles in vivid colours were widely used in various buildings, using mostly vegetal arabesque motifs, of which the most dramatic early example is the Green Mosque and Green Tomb in Bursa. Various examples of tilework from this century seem to show possible Iranian influence and connections to Timurid art. A distinctive style of blue-and-white fritware, influenced by Chinese motifs and often attributed to an early stage of Iznik tilework, is evidenced by the late 15th century and characterizes the early 16th century. Iznik tiles became highly favoured during the rest of the 16th century and reached their artistic peak in the second half of the century. They featured stylized floral and vegetal motifs in blue, white, red, and green colours. The Iznik industry declined by the end of the 17th century, with production of lower-quality tiles shifting to Kütahya. In the early 18th century, a revival of tile art was attempted through the establishment of a new workshop at Tekfursaray in Istanbul, but ultimately the industry faded after this and tile decoration lost its importance.
Painted decoration is a highly visible feature of Ottoman interiors, especially in domes and on upper walls. However, buildings were frequently repainted during later restorations and, as a result, relatively little of the original painted decoration in mosques and palaces has been preserved up to the present day. Surviving examples show that painted designs were related to those of other mediums, including tiles and manuscript decoration, and that floral motifs predominated. Until the 16th century, these motifs remained rather formal and stylized, but from the late 17th century onward they began to change under increasing Western European influence. By the 19th century, European-style motifs were directly incorporated into Ottoman decoration and European techniques such as trompe-l'œil were introduced.
Compared to earlier Seljuk decoration, stone carving occupied a more subtle role in Ottoman architecture. Until the classical period, three-dimensional muqarnas or "stalactite" decoration was the most prominent motif used in entrance portals, niches, columns capitals, and under minaret balconies. Starting in the 18th century, motifs influenced by or borrowed from the European Baroque took over.
Tile decoration
Early Ottoman tilework
Some of the earliest known tile decoration in Ottoman architecture is found in the Green Mosque in Iznik, whose minaret incorporates glazed tiles forming patterns in the brickwork. This technique was inherited from the earlier Seljuk period. Glazed tile decoration in the cuerda seca technique was used in other early Ottoman monuments, particularly in the Green Mosque and the associated Green Tomb in Bursa. The tiles of the Green Mosque complex generally have a deep green ground mixed with combinations of blue, white, and yellow forming arabesque motifs. A large portion of the tiles are cut into hexagonal and triangular shapes that were then fitted together to form murals. Some of the tiles are further enhanced with arabesque motifs applied in gilt gold glazing over these colours. Inscriptions in the mosque record that the decoration was completed in 1424 by Nakkaş Ali, a craftsman native to Bursa who had been transported to Samarkand by Timur after the Ottoman defeat at the Battle of Ankara in 1402. In Samarkand, he was exposed to Timurid architecture and decoration and brought this artistic experience back with him later. Other inscriptions record the tilemakers as being "Masters of Tabriz", suggesting that craftsmen of Iranian origin were involved. Tabriz was historically a major center of ceramic art in the Islamic world, and its artists appear to have emigrated and worked in many regions from Central Asia to Egypt. The artistic style of these tiles – and of other Ottoman art – was influenced by an "International Timurid" taste that emerged from the intense artistic patronage of the Timurids, who controlled a large empire across the region. Doğan Kuban argues that the decoration of the Green Mosque complex was more generally a product of collaboration between craftsmen of different regions, as this was the practice in Anatolian Islamic art and architecture during the preceding centuries.File:Muradiye_mosque_in_Edirne_123.jpg|thumb|Blue and white tilework with Chinese influences at the Murad II Mosque in Edirne
The same kind of tilework is found in the mihrab of the Murad II Mosque in Edirne, completed in 1435. However, this mosque also contains the first examples of a new technique and style of tiles with underglaze blue on a white background, with touches of turquoise. This technique is found on the tiles that cover the muqarnas hood of the mihrab and in the mural of hexagonal tiles along the lower walls of the prayer hall. The motifs on these tiles include lotuses and camellia-like flowers on spiral stems. These chinoiserie-like motifs, along with the focus on blue and white colours, most likely reflect an influence from contemporary Chinese porcelain – although the evidence for Chinese porcelain reaching Edirne at this time is unclear. Tilework panels with similar techniques and motifs are found in the courtyard of the Üç Şerefeli Mosque, another building commissioned by Murad II in Edirne, completed in 1437.
File:Istanbul, padiglione piastrellato, 1472, in stile persiano con mattonelle in stile timuride, arcone d'ingresso 01.jpg|left|thumb|Entrance iwan of the Tiled Kiosk at Topkapı Palace, with Iranian-style tilework based on the banna'i technique
The evidence from this tilework in Bursa and Edirne indicates the existence of a group or a school of craftsmen, the "Masters of Tabriz", who worked for imperial workshops in the first half of the 15th century and were familiar with both cuerda seca and underglaze techniques. As the Ottoman imperial court moved from Bursa to Edirne, they too moved with it. However, their work does not clearly appear anywhere after this period. Later on, the Tiled Kiosk in Istanbul, completed in 1472 for Mehmed II's New Palace, is notably decorated with Iranian-inspired banna'i tilework. The builders were likely of Iranian origin, as historical documents indicate the presence of tilecutters from Khorasan, but not much is known about them. Another unique example of tile decoration in Istanbul around the same period is found on the Tomb of Mahmud Pasha, built in 1473 as part of the Mahmud Pasha Mosque complex. Its exterior is covered in a mosaic of turquoise and indigo tiles inset into the sandstone walls to form geometric star patterns. The work still reflects a traditional style of Anatolian or Persian tile decoration similar to older Timurid examples.
Another stage in Ottoman tiles is evident in the surviving tiles of the Fatih Mosque and in the Selim I Mosque. In these mosques the windows are topped by lunettes filled with cuerda seca tiles with motifs in green, turquoise, cobalt blue, and yellow. Chinese motifs such as dragons and clouds also appear for the first time on similar tiles in Selim I's tomb, built behind his mosque in 1523. A more extravagant example of this type of tilework can be found inside the tomb of Şehzade Mehmed in the cemetery of the Şehzade Mosque. Further examples can be found in a few religious structures designed by Sinan in this period, such as the Haseki Hürrem Complex. The latest example of it is in the Kara Ahmet Pasha Mosque, once again in the lunettes above the windows of the courtyard. Many scholars traditionally attribute these Ottoman tiles to craftsmen that Selim I brought back from Tabriz after his victory at the Battle of Chaldiran. Doğan Kuban argues that this assumption is unnecessary if one considers the artistic continuity between these tiles and earlier Ottoman tiles as well as the fact that the Ottoman state had always employed craftsmen from different parts of the Islamic world. John Carswell, a professor of Islamic art, states that the tiles are the work of an independent imperial workshop based in Istanbul that worked from Iranian traditions. Godfrey Goodwin suggests that the style of tiles does not correspond to either the old "Masters of Tabriz" school or to an Iranian workshop, and therefore may represent an early phase of tilework from Iznik; an "early Iznik" style.
File:Dome_of_the_Rock,_Facade__01.jpg|thumb|Tile decoration on the Dome of the Rock in Jerusalem, added during Suleiman's reign
An important case of Ottoman tile decoration outside the imperial capitals around this time was the refurbishment of the Dome of the Rock in Jerusalem ordered by Sultan Suleiman. During the refurbishment, the exterior of the building was covered in tilework which replaced the older Umayyad mosaic decoration. Inscriptions in the tiles give the date 1545–46, but work probably continued until the end of Suleiman's reign. The name of one of the craftsmen is recorded as Abdallah of Tabriz. The tilework includes many different styles and techniques, including cuerda seca tiles, colourful underglaze tiles, and mosaic blue-and-white tilework. The tiles seem to have been fabricated locally rather than at centers like Iznik, despite the absence of a sophisticated ceramic production center in the region. The identification of Abdallah of Tabriz may also indicate that the tiles were commissioned from the same workshop of Iranian craftsmen who produced earlier Ottoman tiles. This project is also notable as one of the few cases of extensive tile decoration applied to the exterior of a building in Ottoman architecture. This major restoration work in Jerusalem may have also played a role in Ottoman patrons developing a taste for tiles, such as those made in Iznik.