What was the first battle between the Muslims and the Romans?

The first battle between the Muslims and the Romans was the Battle of Mu'tah in Jumada al-Ula of the eighth year of the Hijra. The Muslim army consisted of three thousand fighters, while the Roman army numbered two hundred thousand fighters. In this battle, Ja'far, Zayd ibn Harithah, 'Abdullah ibn Rawahah, 'Abbad ibn Qays, and a group of the Companions were martyred. Then Khalid ibn al-Walid took command and withdrew with the Muslims to Medina.