Salman the Persian
He participated in the Battle of Badr. Muhammad's forces included Abu Bakr, Umar, Ali, Hamza, Mus`ab ibn `Umair, Az-Zubair bin Al-'Awwam, Ammar ibn Yasir, and Abu Dharr al-Ghifari. The Muslims also brought seventy camels and two horses, meaning that they either had to walk or fit three to four men per camel. However, many early Muslim sources indicate that no serious fighting was expected, and the future Caliph Uthman stayed behind to care for his sick wife Ruqayyah, the daughter of Muhammad. Salman the Persian also could not join the battle, as he was still not a free man.