In 1400, Timur's forces invaded Armenia and Georgia, then they took Sivas, Malatya and Aintab. Later on, Timur's forces advanced towards Aleppo with caution, where they tended to construct a fortified camp each night as they approach the city. The Mamluks decided to fight an open battle outside the city walls. After two days of skirmishing, Timur's cavalry moved swiftly in arc shapes to attack the flanks of their enemy lines, while his center including elephants from India held firm Fierce cavalry attacks forced the Mamluks led by Tamardash, governor of Aleppo, to break and flee towards the city gates Afterwards, Timur took Aleppo, then he massacred many of the inhabitants, ordering the building of a tower of 20,000 skulls outside the city.

During Timur's invasion of Syria in the Siege of Aleppo, Ibn Taghribirdi wrote that Timur's Tatar soldiers committed mass rape on the native women of Aleppo, massacring their children and forcing the brothers and fathers of the women to watch the gang rapes which took place in the mosques.