The battle was fought in Kazima (present day Kuwait) by the forces of Khalid ibn al-Walid and the Persians under Hormozd.

Indeed, it was the first battle of the Rashidun Caliphate in which the Muslim army elected to extend its frontiers outside of Arabia, thus initiating the Arab conquests.

[5] Muthana ibn Haritha Shaybani was a tribal chief in north Eastern Arabia, residing close to the Persian border.

To make certain of victory, Abu Bakr decided on two measures: the army would consist entirely of volunteers, and it would be commanded by his best general, Khalid ibn Walid.

Making Al-Hirah (an area in Mesopotamia) the objective of Khalid's mission, Abu Bakr sent reinforcements and ordered the tribal chiefs of northeastern Arabia Muthana ibn Haritha, Mazhur bin Adi, Harmala and Sulma to operate under the command of Khalid.

But before doing so he wrote to Hormozd, the Persian governor of the frontier district of Dast Meisan: Submit to Islam and be safe.

[6] The Persian commander informed the emperor about the threat from Arabia and concentrated an army for the battle, consisting of a large number of Christian Arab auxiliaries.

The men linked themselves together with chains as a sign to the enemy that they were ready to die rather than to run away from the battle field in case of defeat.

Since the Sassanid army was organized and trained for the set-piece battle, this tactic enabled it to stand like a rock in the face of an enemy assault.

[7] Hormozd had deployed his army just forward of the western edge of Kazima, keeping the city covered by his dispositions.