Abu Bakr succeeded Muhammad in leading the umma upon his death in 632 C.E. Abu Bakr was a political advisor to Muhammad and the first converted Muslim. However, as he was not related by blood to Muhammad, some contested his legitimacy. The Sunni faith grew out of recognizing Abu Bakr and the following three Caliphs of Umar, Uthman, and Ali as the Four Rightly Guided Caliphs. Sunnis believe that blood relations shouldn't determine the umma's leader, but that it should be determined by competence and strength.

Shi'a Muslims believe that Muhammad proclaimed succession should be determined on blood lines. As Ali was the husband of Muhammad's daughter Fatima, Shi'a Muslims believe Ali is the legitimate successor of Muhammad. This difference of interpretation has led to violent conflict since the assassination of Ali in 661 C.E. The head of the Shi'a community is known as the Imam.

Sharia, or Holy Law, is a set of laws, principles, and guidelines determined by Islamic legal scholars who set forth jurisprudence based on their interpretation of texts such as the Quran or hadith. Sharia has constantly changed over the centuries based on new interpretations of the texts set forth by Islamic legal scholars. Sharia has at times transcended religious law and has affected societies by setting forth the rules and guidelines a people must live by.

Sufi Muslims are unique from the main branches of Sunni and Shi'a as they express their faith in many ways not confined by dogmatic principles. Known as the mystics of the Islamic faith, Sufis believe each person can develop a connection with Allah. Sufis contributed greatly to the spread of Islam as their practices seemed practical and adoptable by people in foreign lands experiencing Islam for the first time.

Muhammad founded Islam, which is often divided theologically into the Sunni and Shiite sects. Judaism is often considered a sister religion because both Muslims and Jews claim Abraham as the "father" of their religion.

Although controversial to some scholars and in some communities, traditionally some devout Muslim artists had no problem depicting the prophet Mohammed as long as it was done with reverence; in some contemporary Shia areas, such as Iran, artists still depict Mohammed.

It was never commonplace to find depictions of Mohammed in mosques as one would find depictions of Jesus on the cross in churches; usually depictions of Mohammed were done in holy books.

There have always been communities of scholars and religious people who are not comfortable with depictions of Mohammed, it is not just a contemporary issue.

The Qur'an was originally recited by rote. When it was finally written down, it was not illustrated.

While scholars and theologians may argue as to whether this prohibition against depiction is a strength or weakness, they are in agreement that Islam is not the only  religion with such prohibitions; ancient Jewish and Israelite communities found depictions of prophets to be blasphemous, and depictions of Caesar erected in ancient Israel were some of the reasons for the Israelite revolt.

Contemporary Central Asia is mostly Muslim, but until the High Middle Ages it had large populations of Buddhists.

Before the High Middle Ages, Central Asia had Muslim communities but they were not the overwhelming majority.

Worship of the sky god Tengri has been a facet of Central Asian religion for millennium, but it was never the only religion practiced there.

Central Asia had many Christian communities, but it was never mostly Christian.

Central Asia is a difficult place to scratch a living, but it has been consistently populated since prehistory nonetheless.

When the Mon civilization of Southeast Asia was replaced by the kingdom of Pagan, Buddhism was made the official religion of the kingdom.

Neither Christianity nor Islam were designated the official religion of the Pagan kingdom.

Communism had not been theorized yet.

Although some Buddhists consider their faith nontheist or atheistic, Pagan was not official atheist.

Ruling Mongol elites of the Yuan dynasty came into contact with Tibetan Buddhism soon after the state's establishment. 

Ghengis Khan, the most powerful Mongol leader in history, had both Christians and Muslims in his own family; although he personally worshipped Tengri, the sky god. 

The Mongols did come into contact with the Egyptian Mamelukes, but not the Mongols who created the Yuan dynasty in China; rather a different Mongol horde set out westward and invaded the Middle East.

Tonpa Shenrab founded Bon, a Tibetan religion very similar to Buddhism in many ways; in fact Shenrab is often depicted in Bon art as the same as Shakyamuni, or the founder of Buddhism.

Many scholars of comparative religion consider Sikhism, founded by Guru Nanak, a synthesis of Islam and Hinduism.

Siddhartha Gautama, Shakyamuni, an ancient prince from modern Nepal/northern India, is credited with founding Buddhism.

Karl Marx wrote books on the destruction of the aristocratic class, and a coming conflict between workers and capitalists, or the proletariat and the bourgeois.

In some forms of Rastafarianism, Haile Selassie is considered a messianic figure.