Cobalt blue was popular on certain types of ninth-century Iraqi pottery, but never on early Nishapur ceramics, and so this bowl has been attributed to Iraq or perhaps western Iran. Interestingly, the cobalt wares of Iraq, with their stark white, tin-opacified grounds, were made in imitation of Chinese porcelains with blue designs.
1938, excavated at Qanat Tepe in Nishapur, Iran by the Metropolitan Museum of Art's expedition; 1939, acquired by the Museum in the division of finds
Wilkinson, Charles K. Nishapur: Pottery of the Early Islamic Period. New York: The Metropolitan Museum of Art, 1973. no. 3, ch. 6, pp. 183, 194, ill. p. 194 (b/w).