A commentator wrote that this vestment has "Verses from the quran as well as prayers. It was worn not to get magical effects but was a form of worship to put the mind in a particular mode of devotion. It was worn particarly in times of battle not as a piece of cloth to protect against swords and arrows but to have control over ones own mind by not commiting excessive acts in the fits of battle, forbidden by the very words inscribed in that shirt one wore.
Not only the turkish sultans but also the mughals wore them. Examples of mughal shirts are kept in museums in India." (some editing by me)

From the ‘Land of Civilizations, Turkey’ – Catalogue of the Fukuoka Exhibition (Japan), 1985, which was written by the Turkish Ministery of Culture:

Regarding a similar early 16th century garment labeled as ‘Tılsımlı Gömlek / Talismaic shirt’.
“Collarless shirt made of white, tightly-woven and thin linen. Decorated with various suras and verses from the Koran, together with magical letters and numbers used in forecasting the future. The decorative themes and designs on the garment resemble those employed in manuscripts, tiles and ceramics.”

Correspondent: J.M.Criel, Antwerpen.