Sultans of Bengal, Silver tanka of Rukn al-Din Barbak Shah (1459-1474 AD), 'Tughra'-type, Arsah-abad? mint, AH864, G&G B503, 10.15g. Obv: Arabic legend in Tughra calligraphy Rukn al-Dunya wa al-Din Abu al-Mujahid Barbak Shah al-Sultan bin Mahmud Shah al-Sultan. Rev: Arabic legend al-Muwayyad bi-Tayid al-Rahman Khalifath-Allah b'il-Hujjat wa al-Burhan followed by mintname and AH date in numbers. Very fine, Rare.