The Battle of Sallasil, often referred to as the Battle of Chains, was the first battle fought between the Rashidun Caliphate and the Sasanian Persian Empire in April 633. The battle was fought in Kazima by the forces of Khalid ibn al-Walid and the Persians under Hormozd. It was fought soon after the Ridda Wars were over and the Arabian Peninsula was united under the authority of the Caliph Abu Bakr. 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.