a royal descendant of Chinggis Khan or an attempt to defuse an unnecessary conflict on an unwanted front is unclear. Despite his defeat and a subsequent message seeking to defuse the hostility, Tokhtamysh continued to provoke his former protector. While Timur remained in Persia, in the winter of 1387–1388, Tokhtamysh overran Central Asia, where part of his forces besieged Sawran, while another crossed Khwarazm to besiege Bukhara. Timur's commanders prepared to defend Samarqand and other towns against the expected continued advance of Tokhtamysh, and Timur himself headed back from Shiraz to Samarqand with his main forces in February 1388. Learning of the enemy's movements, Tokhtamysh's forces retreated. Timur was now convinced that a serious contest with Tokhtamysh was inevitable. He overthrew the Ṣūfī Dynasty of Khwarazm for its collusion with Tokhtamysh and razed to the ground its capital, (old) Gurgānj, in 1388. Increasingly aware that he was outmatched, Tokhtamysh sought to create an anti-Timurid coalition, reaching out to neighboring rulers (including the Mamluk sultan Barqūq) concerned by Timur's power. Tokhtamysh attempted to take Sawran again in 1388, was driven off by Timur in the snowy January of 1389, but made another attack on Sawran later in the year. It also failed, but Tokhtamysh's forces pillaged the neighborhood and plundered the town of Yasī (now Turkistan) before retreating to safety when Timur defeated Tokhtamysh's vanguard and crossed the Syr Darya in pursuit. Timur seized Sighnaq but then diverted his attention to Tokhtamysh's allies farther east. First Timurid invasion into the Golden Horde and its aftermath Timur determined to take the initiative and strike decisively into Tokhtamysh's core territories. Gathering a large army, he set out in February 1391 from Tashkent, ignored Tokhtamysh's envoys seeking peace, and struck into the territories of the former Ulus of Orda. But for four months of traveling and hunting, Timur failed to catch up with Tokhtamysh, who had seemingly retreated northwards. Only after reaching the headwaters of the Tobol did Timur discover that Tokhtamysh was regrouping to the west, across the Ural and planning to defend the crossing. Timur advanced on the Ural and crossed it farther upstream, causing Tokhtamysh to retreat in the direction of the Volga, where he could expect the arrival of reinforcements from the Crimea, Bolghar, and even Russia. Determined to preempt this, Timur caught up with Tokhtamysh and forced him to give battle at the Kondurcha river, on 18 June 1391.