Sikhism is oftentimes described as a synthesis, or combination, of Islam and Hinduism; it therefore postdates both Islam and Hinduism.

Hinduism is thousands of years older than Islam.

Hinduism is older than Jainism.

Christianity predates Sikhism.

Judaism predates Sikhism.

The Knights Templar and the Knights Hospitaller were militant religious groups that fought for Christendom (and their own personal wealth) during the Crusades. Both groups became immensely rich and powerful following the conquest of Jerusalem in 1099, during the First Crusade. They continued to fight in European wars, particularly against the forces of Islam, for several centuries.

The word Islam means submission or surrender in reference to whom Muslims believe to be the one true God, Allah. Islam was created in the predominantly polytheistic society of Mecca on the Arabian Peninsula. Surrendering to a monotheistic God was a radical concept that quickly attracted many followers placing their unwavering faith in Allah. Islam is also derived from the root word 'salam' which can mean peace and safety.

After the death of the Prophet Muhammad, Islam spread rapidly around the Middle East, Central Asia, North Africa, and the Iberian peninsula. Within one hundred years of the death of the Prophet Muhammad, Islam was the dominant force in territory as far apart as Spain and Iran.

Zoroastrianism was the state religion of the classical Persian Empire and was widely practiced in the Middle East (particularly modern-day Iran) until the Islamic conquest of Persia in the seventh and eighth centuries.

The repeating patterns found in most early Islamic art and architecture are usually attributed to Islam's unwillingness to depict the prophet Muhammad, which led to a distinctive style devoid of iconography. As such, Islamic art was a dramatic departure from that of Christian churches, although the mosque in Corboda was eventually converted into a cathedral after the end of Islamic rule.

The initial spread of Islam, in the turbulent years after the death of the Prophet Muhammad, was mostly carried out through violent conquest. But, in the many centuries since, the bulk of the spread of Islam has been undertaken along trade routes. Arab traders brought Islam to India in the seventh century and spread the religion deep into Sub-Saharan Africa and Central Asia over the next several centuries.

Lay investiture refers to the ability of secular rulers to appoint (or “invest”) individuals in church positions. Lay investiture was common in Europe in the ninth, tenth, and eleventh centuries and led to many disputes between secular rules and the church authorities. The situation was partially resolved in 1122 with the Concordat of Worms, which resolved the dispute between the papacy and the Holy Roman Empire over who had the authority to appoint church officials.

During the Middle Ages religious tolerance was generally greater in the Dar al-Islam than it was in Christian Europe. Muslim authorities insisted on political submission of conquered peoples, but they did not (generally) force conquered peoples into conversion. This was in stark contrast to Christian Europe where non-Christians were routinely forced into conversion (most notably the Jewish population of Spain during the Spanish Inquisition).

The Sunni-Shiite division, which divides Muslims to this day, occurred in the mid-seventh century, less than a hundred years after the foundation of Islam. The division occurred as a result of different interpretations over who should hold power in Islam after the death of the Prophet Muhammad.