Battle of Khaybar
Abu Bakr took part in the Battle of Khaybar. Khaybar had eight fortresses, the strongest and most well-guarded of which was called Al-Qamus. Muhammad sent Abu Bakr with a group of warriors to attempt to take it, but they were unable to do so. Muhammad also sent Umar with a group of warriors, but Umar could not conquer Al-Qamus either. Some other Muslims also attempted to capture the fort, but they were unsuccessful as well. Finally, Muhammad sent Ali, who defeated the enemy leader, Marhab.