Al-Muthanna, commander of the Muslim Arabs in al-Hira, had asked Abu Bakr and later Caliph Umar for reinforcements against the Sasanians in Mesopotamia, who were fighting back.
Umar chose Abu Ubayd who volunteered first, although he was not among the Muhajirun or Ansar (the companions of Muhammad),[3] and dispatched him.
Abu Ubayd arranged a force of 1,000 from his Thaqif tribe and increased his numbers on the way north.
[5] The combined Arab forces conducted raids on the plains between al-Hira and Ctesiphon (the Sawad).
[6][7][8] Abu Ubayd was the father of the revolutionary leader al-Mukhtar al-Thaqafi, who rebelled against the Umayyads to revenge the Karbala event during the Second Fitna.