Bowl decorated with underglaze technique, Ilkhanate Period, 14th century AD. Iran, Sultanabad.
With the Seljuk Empire dominating Iran important developments have started in the ceramics arts. Especially cities like Rey, Kashan, Sultanabad and Nishapur and in Syria Raqqa became the most prominent ceramic centres. In Iran between the 11th and 13th centuries the ceramics produced in these cities demonstrated a lot of progress, and use of many techniques such as underglaze, mono coloured glaze and luster started in the Seljuk tradition. In the underglaze technique decorations are applied under a transparent glaze, which after firing becomes a thin layer of glass showing the colours under it vividly.