Mohammed Shah, a feeble irresolute man, was appointed by Fate to hold the sceptre of India at the moment when she was to meet her fiercest foe. Thamas Kouli Khan, better known as Nadir Shah, had raised himself to the throne of Persia and, like all usurpers, felt the need of strengthening himself at home by a successful foreign war. He accordingly invaded India, at the head of a small force of hardy fighters, who, in the words of Nadir's grandiloquent Persian biographer, "threw the shadow of their sabers across the existence of their foes." In short they killed all before them and entered the Punjaub early in the year 1739, by pretty much the same route as that followed by Baber, the ancestors of the Moguls. But the Moguls were changed since the days of Baber. Mohammed Shah was completely defeated the moment he encountered Nadir Shah. However, booty, rather than territory, was the object of the invader, so he did not dethrone Mohammed, but only levied tribute from him. The defeated Mogul gave an unheard-of quantity of jewels to Nadir Shah "who was at first reluctant to receive them, but at length consented to place the seal of his acceptance upon the mirror of his request." Such reluctance is very foreign to the generally rapacious and grasping character of Nadir Shah, and probably existed only in the flowery imagination of the writer of his life. Having become aware that the Koh-i-nûr was not among the treasures he had already sealed with his acceptance, Nadir Shah set about hunting for it, and at last a traitor was found who betrayed the secret of its hiding-place. A woman from the harem told the Persian king that the coveted diamond lay hidden in the folds of Mohammed's turban, which he never took off. Nadir accordingly one day invited his helpless friend, Mohammed, to exchange turbans with him in sign of their everlasting friendship. As in the time of the first free-will offering to Baber two centuries before, the Koh-i-nûr was once again to pass from the conquered to the conqueror, from the weak to the strong. It is said that Nadir Shah, overjoyed at the beauty of the gem he had thus cleverly filched from his ally, called it "Koh-i-nûr" (i.e. the Rock of Light) the first time that he laid eyes upon it. If this is really a fact it is very singular. It is indeed strange that Jehangir, who was so fond of descriptive names compounded with Light, should have left it to the enemy of his race to endow one of his favorite diamonds with this poetical title. One would prefer to think that he had called his diamond the Rock of Light just as he had called his wife the Light of the World.