Thomas Aquinas was part of a growing scholastic movement in late medieval Christianity, meaning he believed that knowledge was important and reason could coexist with faith. Ideas about the duality of Christ and the cosmos come from Nestorianism and Manichaeism respectively, both of which are much earlier Christian belief systems. Justification through faith alone is a tenet of the Protestant Reformation, which came centuries after Aquinas.

Although early Protestant sects existed in the late medieval period, this new form of Christianity was not widely practiced until the sixteenth century. Martin Luther's 95 Theses, posted in 1517, marked the beginning of what came to be known as the Protestant Reformation.

The Abbasid Caliphate was founded by descendants of the Prophet Muhammad's uncle, al-Abbas and overthrew the Umayyad Caliphate.

The Five Pillars of Islam are Shahada, Salat, Zakat, Sawm, Hajj. The Shahada is the profession of faith all Muslims must make that "There is no god but God (and) Muhammad is the messenger of God." It is mandatory that one must recite the Shahada to become Muslim. Salat is the daily prayer that Muslims must make five times a day in the direction of Mecca. Salat is traditionally performed at dawn, noon, afternoon, evening, and night though it may be modified based on one's geographic location. Zakat is alms-giving or charity. Zakat is expected of those who have surplus to give, but not of those who do not. Sawm is fasting during Ramadan, the ninth month of the Islamic calendar. One cannot eat between dawn and dusk during the fasting period. Hajj is the pilgrimage to Mecca that all Muslim who have the means to do so are expected to make once in their life.

Muhammad began to receive the message of Allah through the archangel Gabriel in 610 C.E. Muhammad would go to meditate on the mountain near Mecca called Jabal an-Nour in a cave known as Hira. Muhammad began to speak publicly about the messages transmitted to him by Gabriel, signaling the beginning of the Islamic faith.

The Qur'an is divided into 114 surahs. The surahs are not listed in chronological order in the Qur'an as they were revealed to Muhammad. The first 24 surahs are Medinan, or revealed to Muhammad in Medina. These surahs are generally longer deal with concrete aspects of Muslim life. The other 86 surahs are known as the Meccan surahs. They are often shorter and deal with religious and spiritual aspects of the Muslim faith.

The hadith are important in the Islamic faith as they are reported to be the spoken word of Muhammad. The hadith can be used in matters of jurisprudence, meaning they can be used to form Islamic Holy Law. Many hadith are contested as to their veracity and hadith can only be confirmed with multiple accounts attributing the words being spoken by Muhammad.

Muhammad had to leave Mecca in 622 due to his religious teachings. Mecca was a predominantly polytheistic society and Muhammad's monotheistic teachings threatened the social order created by Mecca's elites. Muhammed and his followers fled to Medina, or "the City" during what is known as the Hijra.

Umma was the term given to the followers of Muhammad who fled with him to Medina in 622 C.E. The term has been used to take on a greater meaning, denoting the entire "community of the faithful" in Islamic culture. The Umma now extends to people all over the world and includes over one billion followers.

Muslims recognize Abraham, Moses, and Jesus as important religious figures and prophets. However, the name "the seal of the prophets" denotes that Muhammad is the last in the line of prophets and he has given the world the true word of Allah. Muslims do not believe there will be another prophet after Muhammad, thus denoting him as "the seal".