Muhammad's mission, like many other prophets, was to call people to the worship and submission of the one true God. After his death this mission was left to those whom followed his teachings. Those who truly followed in the Prophet's foot steps were proclaimed The Rightly Guided Caliphs. They were Abu Bakr, 'Umar, Uthman and Ali, and were the Four Rightly Guided Caliphs, all of which were amongst the earliest and closest companions of the Prophet Muhammad. Each of these Caliphs contributed greatly to the development of Islam as well as the contradictory emergence of the Sunni and Shi'ite schism.
Abu Bakr was the first of the four Caliphs and ruled from 632-634 A.C. Abu Bakr was unfortunate to have the burden of leadership placed on him during the most sensitive of Muslim times. Since the death of Muhammad was quickly spreading, many Muslims and tribes decided to rebel, refusing to pay Zakat. Also, many claimed that the prophethood of Muhammad had been placed on them, this only made the tribes revolt stronger. He had to deal with the threat of two powerful empires, the Roman Empire and the Persian, of which threatened Islamic state in Medina. Abu Bakr himself led a charge against the revolting tribes who attacked Medina and forced them to retreat. Although the threat of the Roman army still remained, Muhammad had already sent out an army and when he died, Abu Bakr took over. With fierce determination he said
"I shall send Usama's army on its way as ordered by the Prophet, even if I am left alone."
Throughout the rule of Abu Bakr, troops went from one victory to another from attacking Romans. Another contribution of the Caliph was that he encouraged many of Muhammad's friends to commit his teachings to memory. Memories all of which were written down to form the Qu'ran. All together without his leadership; the people