The inscription could either be part of a Qu'ranic quotation (sura al-hashr (lix), parts of v.23, or one of the ninety-nine attributes of God "The All-compeller".
"There are no extant Ottoman buildings with underglaze tiles from 1529 until 1548" (Atasoy, Nurhan and Raby, Julian: Iznik, The Pottery of Ottoman Turkey, London, 1989, p.129). The present tile is a very rare survival from this period. In addition to the blue and turquoise colour scheme, it also has small touches of green in the arabesques in the corners, thereby partially disproving Atasoy and Raby when they suggest that "tilework in the second quarter of the sixteenth century does not seem to reflect the colour changes taking place in the production of vessels" (p.129).
It is only a pity that not more of this very impressive inscription has survived, and, even more so, that there is no record of which building it was designed for. It does however demonstrate clearly the burgeoning taste for blue ground cartouches containing powerful white inscriptions flanked by white spandrels decorated in more colours, a combination which became such a feature of the most important commissions of the third quarter of the century (see for example lot 337).