John Carswell has suggested that the roundels seen here are versions of those which appear on Chinese blue and white porcelain which in turn derive from depictions of the armillary sphere of Manuel I of Portugal (1461-1521). An example of the Chinese variant is in the Topkapi Palace (Regina Krahl, Chinese Ceramics in the Topkapi Saray Museum, London, 1986, no.812, p.590). Another dish with very similar layout in the Sadberk Hanim Museum, Istanbul, shows the link very clearly. One roundel clearly derives from the version of the royal Portuguese arms found on the Chinese original, while another roundel has the vestiges of the armillary sphere (John Carswell, Iznik, London, 1998, pl.76, p.96). A similar cover was excavated at Iznik (Oktay Aslanapa, Serare Yetkin and Ara Altun, The Iznik Tile Kiln Excavations, The second round, Istanbul, 1989, p.176).
While it seems very probable that this design was indeed the general source of the idea of free-floating interlace roundels, the Iznik potters developed it so that the original was lost. A further dish in the Sadberk Hanim Museum has stylised the design further and thus, like the present example, has four similar red roundels whose design only very loosely relates to the armillary sphere (Laure Soustiel, Splendeurs de la Céramique Ottomane, Paris, 2000, no.29, p.77). The roundels on the present dish are also closer in design to those on a mosque lamp from the Godman Collection in the British Museum (Nurhan Atasoy and Julian Raby, Iznik, the Pottery of Ottoman Turkey, London, 1989, pl.768). The ultimate source of the design found within the roundels of this group of vessels would appear however to have derived from book illumination. A very similar design is found in the roundels of a Qur'an now dispersed but of which the largest part is in the John Rylands Library, Manchester (David James, Qur'ans of the Mamluks, London, 1988, cat.59, pp.173-177, esp.fig.123a). The same roundel can also be found in the main illuminated page of the large fourteenth century Qur'an in this sale (lot 33), and again on the slightly earlier high tin bronze bowl dating from the thirteenth century (lot 82).