The son of one figure with this title lost to the Umayyads at Karbala.
The first holder of this title fought rebellious taxpayers in the Ridda Wars. The first two occupants of this office employed Khalid ibn al-Walid, who crushed the Sassanids at the Battle of Qadisiyya. The Battle of Yarmouk was climactic in a conflict between holders of this office and Emperor Heraclius. One holder of this title was rejected by a group of erstwhile followers known as the Khajirites. The death of one holder of this position prompted the First Fitna. The son of one figure with this title lost to the Umayyads at Karbala. Their number includes Abu Bakr, Umar, Uthman, and Ali. For 10 points, give this title, held by four "Rightly Guided" individuals known as the Rashidun.
The first holder of this title fought rebellious taxpayers in the Ridda Wars.
{Caliphs} [or {al}-{Khufala ur}-{Rashidun} before read; or {Rightly Guided Caliphs}; or {Righteous Caliphs}]