Battle of Siffin
The name Kaysānīyya must have been based on the kunya (surname) Kaysān, allegedly given to al-Mukhtar by Ali, or the name of a freed mawlā of ʿAli who was killed at the Battle of Siffin called Kaysān, from whom it is claimed Al-Mukhtar acquired his ideas. Similarly, it may be named after Abu Amra Kaysan, a prominent mawālī and chief of al-Mukhtar’s personal bodyguard. Others claim that either ʿAli or Ibn al-Ḥanafiya named al-Mukhtar ‘Kaysān,’ because of his ingeniousness.