The inscription on this panel is Qur'an XVI, sura al-nahl, v. 128 which translates 'Surely Allah is with those who restrain themselves and those who are benevolent'.
The present panel relates very closely to two, also laid down on gilt copper mounts, which are each signed by Muhammad Reza in small thuluth towards the bottom of the panels (sold in these Rooms, 23 April 1996, lot 224 and Sotheby's, London, 1 April 2009, lot 111). It is probable that this refers to Muhammad Reza al-Imami who contributed the inscriptions on important monuments in Isfahan and Mashhad in the second half of the 17th century (Robert Hillenbrand, 'Safavid Architecture', The Cambridge History of Iran, Vol. VI, Cambridge, 1986, pp. 787, 803 and 837). The same calligrapher worked on other commissions on the same scale as the present piece, demonstrated by two wooden panels (G. Fehérvári and Y. Safadi, 1400 Years of Islamic Art, a Descriptive Catalogue, Khalili Gallery, London, 1991, nos. 157a-f, p.230). Such are the stylistic similarities between these three panels that it seems reasonable to suggest that they were all part of the same commission and that the present panel is thus also the work of the celebrated Muhammad Reza.
Another group of similar panels, probably from a closely related structure, includes one in the British Museum (Y.H. Safadi, Islamic Calligraphy, London, 1978, pl.190, p.37; The Arts of Islam, exhibition catalogue, London, 1976, no.235, p.200) and another sold in these Rooms, 16 October 2001, lot 323. All have the same cusped oval format enclosing inscription on very fine scrolling ground. That in the British Museum is dated AH 1005/1693-94 AD, enabling the present example to be dated very precisely.
Although a number of Safavid cut steel panels are known, few remain with the original backing plates, which give a far clearer idea of how the panels must have looked when still attached to their original structures. Another with its original backing plate is in the David Collection (Kjeld von Folsach, Art from the World of Islam in the David Collection, Copenhagen, 2001, no. 526, p. 328).