In the twelfth and thirteenth centuries under Seljuk rule in Anatolia, a hard white composite was applied to great effect to tile mosaic decorations and for pottery vessels. The production of this white ware appears to have lapsed in the thirteenth century and succeeded by a cruder, red earthenware, covered with a white slip and painted under a lead glaze in blue-green, purple and black. This is misnamed Miletus ware, so called after the town of Milet in southwestern Anatolia. Recent excavations showed that they were actually made in Iznik (as well as Kutahya), thus establishing this town as a center for the manufacture of pottery long before the classical fifteenth and sixteen century, white-bodied wares associated with it. Iznik was conquered by Seljuks in 1075 and became their western capital.
The technical and aesthetic excellence attained by this early blue and white pottery was without precedent in the Islamic world and was the results of the attempts to compete with Chinese porcelains. These developments are probably due to the settlement of master potters in the town and the establishment of links with the design atelier (nakkashane) instituted by Sultan Mehmed the Conqueror in Istanbul.
Iznik pottery comes in well defined and standardized shapes of mosque lamps (cami kandili), footed basins (ayakli legen), bowls (kase), covered bowls (kapakli kase), dishes (tabak/sahan), tazza (tas), candlesticks (samdan), jugs (bardak), tankards (masrapa), jars (kavanos), ewers (ibrik), carafes and water bottles (surahi). The largest open shape does not exceed 45.5 cm in diameter and largest object do not exceed 49 cm height. Most surviving pieces are patterned and some are gilded (altunli).
The body of the pottery was made of 80% silica, 10% white clay and 10% glass frit. To create a brilliant white ground on which to paint, the body was coated with a thin layer of slip. In present day Kutahya, the slip consists of 75% quartz and 25% clay. Coloring consisted of seven colors; blue, turquoise, green, black, purple, red and gray. All colors were prepared as mixtures of pigment and glass frit, comminuted in a wet quern. After painting with these glassy pigments, the pottery was covered with a transparent colorless glaze. The Iznik glaze was a lead-alkaline-tin mixture like the body frit, but the lead was 30%, compared to 50% for the body frit. The firing temperature was a comparatively low 850-900 degrees C.
The Ottoman pottery has exerted a long-standing and widespread appeal in Europe and especially in the second half of the 19th century they become prized collectables. The unfortunate result of Europes interest was that ill-informed European scholars created a legacy of confusion and misleading labels such as Persian ware, Rhodian ware, Damascus ware, Kutahya ware and Golden Horn ware, in successive attempts to define the Ottoman pottery of Iznik.
Reference:Yanni Petsopoulos, Iznik, The Ottoman Pottery of Turkey", Alexandria Press, London, 1989.