He played an important role in the victory of al-Ma'mun in the Abbasid civil war, but was executed at his orders when he protested against the power of the Sahlid family that dominated his court.
Isa was forced to renounce his claim on the throne in favour of al-Mansur's son, al-Mahdi (r. 775–785), who had Harthama brought to Baghdad in chains and kept him under arrest throughout his reign.
In the final stage of the siege, Harthama tried unsuccessfully to secure the surrender and life of al-Amin, by sending a boat to ferry him over the Tigris.
[2][3][7] In response to the news of his execution, Harthama's son Hatim, the governor of Arminiya, led a rebellion that was however cut short by his own death.
[2][3] Another son, A'yan, governor of Sistan c. 820, is also known, and his descendants through Hatim continued to occupy high offices until well into the 9th century.