76 THE TURKS IN DELHI claimed it by his coinage. The whole of the dominions of Aybek were now in the hands of his slave, and expeditions into Malwa as far as Ujjain completed, in 1234, the submission of all India north of the Vin- dhyas. The seal was set on a career of unvaried success when, in 1229, the caliph of Baghdad sent an embassy of state to invest Altamish with the robe of office as recognized sovereign of India. Thenceforth the king inscribed upon his coins not only the proud legend, " The Mighty Sultan, Sun of the Empire and the Faith, Conquest-laden, Il-tutmish," but also " Aid of the Com- mander of the Faithful," Nasir-Amir-al-Muminin. The broad silver pieces on which these titles appeared were new to the currency of India. Hitherto the invaders had issued small billon coins of the native form, in- scribed with their names in Sanskrit and sometimes in Arabic characters, and bearing symbols familiar to the Hindus, such as the bull of Siva and the Chohan horse- men. Altamish was the first to introduce a purely Arabic coinage, such as had long been in use in countries farther west, and to adopt as his standard coin the silver tanka, the ancestor of the rupee, weighing 175 grains, and thus exactly corresponding to the English florin. Gold tankas of the same weight were introduced somewhat later by Balban. For ten years after the death of Altamish, in 1236, his kingdom suffered from the weakness and depravity of his sons. The first, Firoz Shah, was a handsome, generous, soft-hearted, convivial young fool, who spent
