<P> Timur then went north to begin his Georgian and Golden Horde campaigns, pausing his full - scale invasion of Persia . When he returned, he found his generals had done well in protecting the cities and lands he had conquered in Persia . Though many rebelled, and his son Miran Shah, who may have been regent, was forced to annex rebellious vassal dynasties, his holdings remained . So he proceeded to capture the rest of Persia, specifically the two major southern cities of Isfahan and Shiraz . When he arrived with his army at Isfahan in 1387, the city immediately surrendered; he treated it with relative mercy as he normally did with cities that surrendered (unlike Herat). However, after Isfahan revolted against Timur's taxes by killing the tax collectors and some of Timur's soldiers, he ordered the massacre of the city's citizens; the death toll is reckoned at between 100,000 and 200,000 . An eye - witness counted more than 28 towers constructed of about 1,500 heads each . This has been described as a "systematic use of terror against towns...an integral element of Tamerlane's strategic element", which he viewed as preventing bloodshed by discouraging resistance . His massacres were selective and he spared the artistic and educated . This would later influence the next great Persian conqueror: Nader Shah . </P> <P> Timur then began a five - year campaign to the west in 1392, attacking Persian Kurdistan . In 1393, Shiraz was captured after surrendering, and the Muzaffarids became vassals of Timur, though prince Shah Mansur rebelled but was defeated, and the Muzafarids were annexed . Shortly after Georgia was devastated so that the Golden Horde could not use it to threaten northern Iran . In the same year, Timur caught Baghdad by surprise in August by marching there in only eight days from Shiraz . Sultan Ahmad Jalayir fled to Syria, where the Mamluk Sultan Barquq protected him and killed Timur's envoys . Timur left the Sarbadar prince Khwaja Mas'ud to govern Baghdad, but he was driven out when Ahmad Jalayir returned . Ahmad was unpopular but got some dangerous help from Qara Yusuf of the Kara Koyunlu; he fled again in 1399, this time to the Ottomans . </P> <P> In the meantime, Tokhtamysh, now khan of the Golden Horde, turned against his patron and in 1385 invaded Azerbaijan . The inevitable response by Timur resulted in the Tokhtamysh--Timur war . In the initial stage of the war, Timur won a victory at the Battle of the Kondurcha River . After the battle Tokhtamysh and some of his army were allowed to escape . After Tokhtamysh's initial defeat, Timur invaded Muscovy to the north of Tokhtamysh's holdings . Timur's army burned Ryazan and advanced on Moscow . He was pulled away before reaching the Oka River by Tokhtamysh's renewed campaign in the south . </P> <P> In the first phase of the conflict with Tokhtamysh, Timur led an army of over 100,000 men north for more than 700 miles into the steppe . He then rode west about 1,000 miles advancing in a front more than 10 miles wide . During this advance, Timur's army got far enough north to be in a region of very long summer days causing complaints by his Muslim soldiers about keeping a long schedule of prayers . It was then that Tokhtamysh's army was boxed in against the east bank of the Volga River in the Orenburg region and destroyed at the Battle of the Kondurcha River, in 1391 . </P>

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