Answer:
The rise of Islam is intrinsically linked with the Prophet Muhammad, believed by Muslims to be the last in a long line of prophets that includes Moses and Jesus. Because Muhammad was the chosen recipient and messenger of the word of God through the divine revelations, Muslims from all walks of life strive to follow his example. After the holy Qur'an, the sayings of the Prophet (hadith) and descriptions of his way of life (sunna) are the most important Muslim texts.
Muhammad was born into the most powerful tribe in Mecca, the Quraish, around 570 A.D. The power of the Quraish derived from their role as successful merchants. Several trade routes intersected at Mecca, allowing the Quraish to control trade along the west coast of Arabia, north to Syria, and south to Yemen.
Mecca was home to two widely venerated polytheistic cults whose gods were thought to protect its lucrative trade. After working for several years as a merchant, Muhammad was hired by Khadija, a wealthy widow, to ensure the safe passage of her caravans to Syria. They eventually married.
When he was roughly forty, Muhammad began having visions and hearing voices. Searching for clarity, he would sometimes meditate at Mount Hira, near Mecca. On one of these occasions, the Archangel Gabriel (Jibra'il in Arabic) appeared to him and instructed him to recite "in the name of [your] lord." This was the first of many revelations that became the basis of the Qur'an, the holy book of Islam. These early revelations pointed to the existence of a single God, contradicting the polytheistic beliefs of the pre-Islamic Arabian Peninsula.
Initially overwhelmed by the significance of what was being revealed to him, Muhammad found unflinching support in his wife and slowly began to attract followers. His strong monotheistic message angered many of the Meccan merchants. They were afraid that trade, which they believed was protected by the pagan gods, would suffer. From that point forward, Muhammad was ostracized in Mecca. For a time, the influence and status of his wife and his uncle, Abu Talib, the chief of the clan, protected Muhammad from persecution. After they died, however, Muhammad's situation in Mecca became dire.
Emigration became the only hope for Muhammad and his followers' survival. In 622, they headed to Medina, another oasis town, where they were promised freedom to practice their religion. The move from Mecca to Medina is known as the hijra—the flight—and marks year 1 of the Islamic, or hijri, calendar.
In Medina, Muhammad continued to receive divine revelations and built an ever-expanding community around the new faith. The conflict with the Quraish continued, but after several years of violent clashes, Mecca surrendered. Muhammad and his followers soon returned and took over the city, destroying all its pagan idols and spreading their belief in one God
Accounts of the ascension (mi'raj ) of Muhammad have captured the imaginations of writers and painters for centuries. One night, while the Prophet was sleeping, the Archangel Gabriel came and led him on a journey. Mounted on the heavenly steed Buraq, Muhammad traveled from the Ka'ba in Mecca to the "Farthest Mosque," which Muslims believe to be the Al-Aqsa Mosque in Jerusalem. There he prayed with other prophets such as Moses, Abraham, and Jesus, and ascended to the skies, where he was led by Gabriel through Paradise and Hell, and finally came face to face with God. He then returned to earth to continue spreading the message of Islam. According to Islamic belief, Muhammad was the only person to see Heaven and Hell while still alive.
After the Prophet's Death: Emergence of Shi'i and Sunni Sects of Islam
When Muhammad died in 632, he had not named a successor. One faction, the Shi'a, believed that only individuals with direct lineage to the Prophet could guide the Muslim community righteously. They thought that 'Ali, Muhammad's closest surviving blood male relative, should be their next leader (caliph). The other faction, the Sunnis, believed that the Prophet's successor should be determined by consensus and successively elected three of his most trusted companions, commonly referred to as the Rightly Guided Caliphs (Abu Bakr, 'Umar, and 'Uthman), as leaders of the Muslim community; 'Ali succeeded them as the fourth caliph.
Today the Islamic community remains divided into Sunni and Shi'i branches. Sunnis revere all four caliphs, while Shi'is regard 'Ali as the first spiritual leader. The rift between these two factions has resulted in differences in worship as well as political and religious views. Sunnis are in the majority and occupy most of the Muslim world, while Shi'i populations are concentrated in Iran and Iraq, with sizeable numbers in Bahrain, Lebanon, Kuwait, Turkey, Pakistan, and Afghanistan.