In 1212, wearied by her continual campaigns, and sorrow-stricken at the death of her husband and her greatest general, Tamara died, and left the throne to her son, Giorgi Lasha, at that time eighteen years of age. The young king was no sooner crowned than Ganja revolted, and this was soon followed by a still greater calamity, the invasion of Genghis Khan. Giorgi led 90,000 troops against the Mongols, but was defeated. In the meantime the Shah of Persia had asked for the hand of the beautiful Rusudan, and the Shah of Shirvan made a like demand. Giorgi promised his sister to the latter, but he died in 1223. Rusudan now became queen, and rejected both suitors in favour of Mogit Eddin, Lord of Erzerum. The Sultan of Khorassan thereupon desolated Georgia and took Tiflis, and the Persians and Mongols together made terrible havoc for a time. Rusudan at last submitted to the Mongols, and sent her son to the great Khan as a hostage. Georgia had now sunk very low indeed, and in 1243, on the death of Rusudan, her son, David IV., and her nephew, David V., divided the kingdom between them. Henceforth Kartli and Imereti were independent. For the next 200 years we read of nothing but battles, sieges, raids, and in 1445 King Alexander completely destroyed the unity of the kingdom by dividing it among his three sons. He gave Kartli to Vakhtang, Imereti to Dimitri, Kakheti to Giorgi. In course of time Mingreli, Guri, Apkhazi, Svaneti, all revolted, and the land became the prey of Turks and Persians alternately, although even in its distracted condition, its people never lost their bravery, and were always respected by their enemies. Now and then the Mahometans succeeded in conquering one or other of the provinces, but it was never long before they were driven out again, and fire and sword carried into their own land. Towards the end of the sixteenth century we find the country divided between the two great Mahometan powers, who had long made it their battle-field. Mingreli, Guri, Saatabago, and Imereti were held by the Turks; Kartli, Kakheti, Somkheti, and Kartuban voluntarily submitted to Persia, and were, in consequence, repeatedly devastated by the Tatar allies of the Ottoman Empire. In 1586 King Alexander II. of Kakheti sent ambassadors to the Tsar Feodor Ivanovich, asking for help, and a treaty was signed, according to which the Russian monarch agreed to protect Kakheti against the Turks, and to send troops to the Caucasus for this purpose. Shah Abbas the Great made no objection to this treaty, for he himself was anxious to gain the alliance of the Muscovites against Turkey.