This is an extremely unusual bowl. The design appears to be copied, possibly directly, from a Kashan bowl dating from the start of the 13th century. The combination of the roundness of the sides, the thickness of the potting and the form of the foot precludes this being its date and place of manufacture. These points recall a number of bowls either decorated in blue or black under a similarly slightly treacly white glaze that have been dated to the 15th century.