Muhammad soon began to preach his revelations to the people of Mecca (his teachings were later written down by his followers in the book called the Koran) and introduced the five pillars of faith:.
1. Shahada "profession of the Islamic faith.
2. Salat "praying 5 times a day while facing towards Mecca.
3. Zakat "the giving of alms to the poor or weak.
4. Siyam "fasting during the month of Ramadan between sunup and sundown.
5. Hajj "traveling to Mecca as a final profession of faith.
An example of the five pillars of faith can be seen in Exploring the Sources of World Civilizations in the article about the Hadith and the Sunna. In the article, Zakat is exemplified by the prostitute that gives food to a dog. Other examples of Salat, Siyam, and Hajj can be seen in the article also. .
The merchants of Mecca were not pleased with Muhammad's teachings and expelled him from Mecca. They believed his teachings would disrupt the economic prosperity of Mecca. Around 622 C.E., Muhammad and his followers were forced to flee Mecca to the north to the city of Medina. This emigration from Mecca to Medina called the Hegira marks the beginning of the Islamic calendar in the Christian year 622. Muhammad had declared a jihad or holy war against the people of Mecca in order to rid Mecca of its evils. By 630 C.E. Muhammad had defeated the people of Mecca and made peace with the Meccans. Two years later Muhammad died suddenly and the merchants of Mecca were Muslim. .
Muhammad's followers decided that no one could replace him as spiritual leader and decided to appoint a supreme leader for the Muslims called a caliph. Since Muhammad had laid out the basic Muslim code of conduct in the Sharia, no one could change Islamic religion or laws, only enforce them. That enforcement was up to the caliph. The caliphs soon busied themselves with spreading the word of Muhammad and Islam throughout the region.