Muslim world:

Between the 8th and 18th centuries, the use of glazed ceramics was prevalent in Islamic art, usually assuming the form of elaborate pottery. Tin-opacified glazing was one of the earliest new technologies developed by the Islamic potters. The first Islamic opaque glazes can be found as blue-painted ware in Basra, dating to around the 8th century. Another contribution was the development of stone-paste ceramics, originating from 9th century Iraq. Other centers for innovative ceramic pottery in the Old world included Fustat (from 975 to 1075), Damascus (from 1100 to around 1600) and Tabriz (from 1470 to 1550).

Please answer a question about this article. If the question is unanswerable, say "unanswerable". Around when were the first opaque glazes developed?
8th century