The Rashidite Caliphate, is the collective term comprising the first four caliphs—the “Rightly Guided” or Rashidun caliphs—in Islamic history and was founded after Muhammad’s death in 632.
After Muhammad’s death in 632, the Medinan Ansar debated which of them should succeed him in running the affairs of the Muslims while Muhammad’s household was busy with his burial. Umar (a Quraish) and Abu Ubaidah ibn al-Jarrah pledged their loyalty to Abu Bakr, with the Ansar and the Quraish soon following suit. Abu Bakr thus became the first Khalifa Rasul Allah (Successor of the Messenger of God), and embarked on campaigns to propagate Islam. First, though, he would have to subdue the Arabian tribes which had gone back on their oaths of allegiance to Islam and the Islamic community. As a Khalifa or caliph he was not a monarch and never claimed such a title nor did his three successors do so.