Delhi Sultanate, Nasir ud-din Mahmud (AH 644-664 /1246-1266 AD) Hadrat Delhi Mint, Gold Tanka, AH 650, Struck on Large Flan, Obv: Arabic legend “al-sultan al-a’zam Nasir ud-dunya wa’l din abu’l muzaffar Mahmud bin al-sultan” within a double circle, “darb hada al sikka bahadrat Delhi fi sanah” in margin, Rev: Arabic legend ”fi ahd al-Imam al-Must’asim amir ul momimin" within a double circle, “darb hada al sikka bahadrat delhi fi sanah” in margin,10.91g, 26.00mm, (G&G # D135), almost completely struck, nice luster, AU-UNC, Extremely Rare.