Monochrome Glazed Enamelled Wall Tiles
The finest examples, that we have seen in the Orhan Bey İmaret (soup kitchen and hospice) (1399), in the Green Mosque, shrine and madrasa (1421-22), in the tombs of the Crowned Prince Ahmet (1429), the Crowned Prince Mahmut (1506) and the Crowned Prince Cem (1474) as well as in the Murat II Mosque, are made of a yellowish white, siliceous clay glazes in the colours such as turquoise, green, ultramarine, white or fluorite violet that were applied singly to each tile, unlined, and then fired. Such tiles were generally used for interiors, for walls as far as the upper part of the windows and sometimes to cover the sarcophagi as well. The hexagonal plates, together with the differently coloured triangles, squares and borders that surrounded them all went to make up large geometrical compositions. Sometimes monochrome glazed tiles were pressed into a mould while the clay was still soft to make relief designs. Inscriptions achieved in this manner are frequently observed on sarcophagi.
On the top of the coloured glaze of the hexagonal tiles in the tombs, plant designs in gold leaf have been applied, the focal point of the pattern being in the center of the tile. The designs are achieved by means of melting the gold leaf or by pressing it on by means of as tamp. This style of ornamentation dates from the Seljuk period and can be seen in the Karatay Madrasa in Konya. It was then passed on to Bursa in the 15th century. Ornamentation of enamelled tiled with gold leaf was achieved by inlaying, and with the use of a brush, after which it was fired at a low temperature. Very few examples of these tiles have survived because they easily get corroded.
The use of enamelled tiles on exterior walls is extremely rare. The plain greenish turquoise tiles which cover the exterior of the Green Tomb and give it its name, formed an entegrity with nature.