The Kara Koyunlu gave the Timurids quite a difficult time and even managed to temporarily occupy the Timurid capital of Herat, which is in present-day Afghanistan.
The conflict between the Kara Koyunlu and the AkKoyunlu was equally ferocious.
In 1435 a Kara Koyunlu leader killed Kara Qasim, the Amir of the AkKoyunlu.