The inscription is as follows:
in naqsh keh nist shabih dar ayyamash
bar charkh neveshteh kelk-e qodrat namash
tasvir-e amir-e jam khadam shaykh'ali ast
kaz ruz-e azal amadeh gard[u]n bamash
The translation reads:
This picture, the like of which does not exist in his time, [And] the pen of power has written his name in heaven, Is the picture of the Amir whose servant is Jam, Shaykh 'Ali, Whose ceiling from eternity, has been heaven.
Shaykh 'Ali Mirza born 1211/1795 was the ninth son of Fath 'Ali Shah. His mother was the daughter of the famous Zandi Commander-in-Chief called Shaykh 'Ali from whom he received his name. He was the Governor of Malayer and Tuyserkan between 1224 to 1250 (1809-1834-5). In 1242/1826-7 he was sent by the Shah to fight the Russian army in Saqqez and Shirvan.
At the time of the accession of Muhammad Shah he was arrested together with nine other princes opposed to the new Shah and imprisoned in the fortess at Ardebil. After four of the princes escaped in 1253/1837-8, he was moved to a prison in Tabriz where he remained until his death in 1263 (1846-7).
He is mentioned as a poet with the penname Shapur, and is described as a courageous prince who wrote nasta'liq well.
In the present painting he appears, like his brother, Hasan 'Ali Mirza, wearing the Qajar crown and with copious jewelled ornaments. As with his brother's portrait, the painting bears a long and poetic inscription, a highly unusual feature, suggesting that this was a commission of great importance. Another portrait of him as a beardless youth with a rather long face is published in Bamdad (see below).
Bamdad, M.: Dictionary of National Biography in Iran, 1700-1900, Terhan, 1966, Vol.II, pp.154-5
Khayyampur, A. ed.:tadhkere-ye negarestan dara by 'Abd al-Razzaq Danbali, Tabriz, 1342 sh, pp. 29-30