The siege of Kath (1372) was an early success during Tamerlane's first expedition into Khwarezm, and was followed by one of the first examples of the atrocities that so often followed when Tamerlane captured a city.
Khwarezm was the area to the north-west of Tamerlane's heartland of Transoxiana, on the delta of the Amu Darya. After the Mongol invasion Khwarezm was split between two of the Mongol hordes, with the north of the area going to the Golden Horde and the south, including Kath and Khiva, to the Chaghatay. At the start of the 1360s power in the northern part of the area had been seized by Husayn Sufi, and during that decade he has also take control of Kath and Khiva.
It was this move that was used by Tamerlane as the pretext for war, although the wealth of the area was probably the real motive. He dispatched a messenger to Husayn, demanding the return of the two cities. Husayn's reply was that he had 'conquered these countries with his sword, and that Timur might recover then the same way, if he could'. After a second diplomatic mission failed Tamerlane prepared to invade.
Tamerlane's army began its advance into Khwarezm in the spring of 773 A.H. or 1372. After an initial skirmish on the Oxus the army reached the city of Kath, still a prosperous place, although its time as ancient capital of Khwarezm had come to an end nearly four hundred years earlier.
The town was defended by two of Husayn's men, Behram Yesaoul as governor and Sheik Muaid as judge. They had one advantage, in that Tamerlane's army didn't contain any siege engineers, and Tamerlane's first attack seems to have been defeated by heavy missile fire from the town. The possibility that the siege might have to be raised is also mentioned, but Tamerlane refused to withdraw without a victory. His men were ordered to fill the ditch around the city, and despite the danger came close to the walls to watch this work and the assault that followed.
Tamerlane's men seem to have swarmed over the defences, capturing the city after fierce fighting in which most of the defenders were killed. In one of the first of the many atrocities that followed Tamerlane the men of the city were massacred and their wives and children taken as slaves, although on the following day they were released.
After this first success Tamerlane advanced towards the Khwarezm capital of Urganch, winning a battle just outside the town. Husayn then retreated back into Urganch, where he was besieged for a short time before dying. He was succeeded by his brother Yusef Sufi, who managed to come to terms with Tamerlane, in return for the hand of his brother's daughter Khan zada in marriage with Tamerlane's oldest son Jahangir. A second military expedition was needed before the princess was delivered, but both the marriage and the peace would be short-lived. Two more expeditions followed before the end of the 1370s, while Jahangir died in 1376.