“Dhimmi” is a term used in premodern Muslim empires to describe non-Muslims who were afforded protected status by the government. These groups included Hindus, Buddhists, Zoroastrians, Sikhs, Jews, and Christians. Muslim governments granted dhimmis complete religious liberty so long as they recognized Islamic political authority. Armstrong emphasizes the relatively peaceful relationship between dhimmis and their Muslim governments (as opposed to Jewish and Muslim minority groups who faced persecution when living under Christian rule) to counteract modern Western stereotypes that portray Islam as an inherently intolerant religion.

Armstrong defines fundamentalism as a quality that can be observed in many contemporary religious movements, regardless of specific tradition; “Fundamentalism is a global fact… There is fundamentalist Judaism, fundamentalist Christianity, fundamentalist Hinduism, fundamentalist Buddhism, fundamentalist Sikhism and even fundamentalist Confucianism” (185). Armstrong argues that fundamentalism’s key characteristic is a vehement suspicion of modernity, and the belief that modern practices are detrimental to religious practice. Fundamentalist groups often form their practices in response to modern secular practices and ideas; as a response to feminism, for example, fundamentalists in various cultures have touted a return to “traditional gender roles,” and imposed restrictive policies on women. Armstrong therefore characterizes fundamentalism, including the Muslim strain of it, as ironically reliant on the very modernity it rebels against.

In its most general sense, the word Imam refers to any leader of a Muslim community; prayer leaders at mosques, for example, take the title of Imam. Shia Muslims, however, use the word to specifically refer to the descendants of Muhammad through his daughter, Fatimah, and son-in-law, Ali, who they believe to be the rightful rulers of the entire Muslim population. See “Shii” below for more on Shia beliefs about the imams.

Jihad is an Arabic word that literally translates to “struggle.” In the context of Islam, it is used to describe the obligation that each Muslim has to resist forces detrimental to their faith. Most frequently, this presents as an internal struggle, wherein the devout strive to rid themselves of un-Islamic impulses and thoughts. Some extremist groups, however, use the term in reference to literal warfare, asserting that the Quran’s doctrine of jihad sanctions violence against those perceived as enemies of Islam. Armstrong is careful to emphasize that the latter interpretation of the term arose years after the death of Muhammad, is not original to the Quran, and does not reflect the beliefs of most Muslims.

The Quran (sometimes spelled “Koran” or “Qur’an”) is Islam’s holy scripture, a transcription of revelations from God that the prophet Muhammad delivered verbally to his followers over the course of roughly 23 years. The Quran consists of 114 surahs (chapters), and can be read in conjunction with hadiths, a body of texts that were compiled after Muhammad’s death that contain anecdotes about his life and words. Like all other major religious texts, the Quran has been reinterpreted repeatedly by its followers, and Armstrong traces this theological development throughout Islam: A Short History.

Shariah refers to the collection of Islamic laws that are derived from the Quran, the hadiths, and the sunnah (a body of literature recorded by Muhammad’s family and followers which recounts his daily habits and religious practices). Since political life is seen by many Muslims as having a religious significance, the legal literature of Islamic societies is necessarily intertwined with their religious literature. Armstrong pays close attention to how various Muslim governments have interpreted and implemented shariah over the course of history.

Shii, or Shia, Islam is a branch of the religion that believes that Ali ibn Abi Talib, Muhammad’s son-in-law and closest male relative at the time of his death, should have inherited rule over the ummah instead of the four Rashidun. Shia Muslims designate the male descendants of Ali and his wife Fatimah as the rightful caliphs, and call them imams. The last of these descendants, Muhammad al-Madhi, disappeared in 874 C.E., but is believed by many Shia to be a messianic figure who will return to earth at the end of time. Theological and political conflicts between Shia and Sunni Muslims are a central theme throughout Islamic history, and thus comprise a large focus of Islam: A Short History.

Sufism is a mystic branch of Sunni Islam. Sufis practice a highly internalized, and oftentimes ascetic, version of Islam that aims to “reproduce… that state of mind that made it possible for Muhammad to receive the revelations of the Quran” (103). Armstrong argues that this movement developed in response the highly-judicial form of Islam promoted by the Abbasid Caliphate. Key Sufi thinkers discussed in Islam: A Short History include Rumi (1207-73), Rabia Basri (d. 801), al-Ghazzali (d. 1111), and Ibn al-Arabi (1165-1240).

Sunni Islam is the largest school of Islam in number of followers. As opposed to Shia Muslims, Sunnis accept the rule of the Rashidun as having been legitimate. Sunni believers also accept the traditional Muslim system of jurisprudence, and derive their name from the sunnah (see entry for “shariah” above), which form the basis of that system. Despite the Sunni branch’s vast majority within Islam, conflicts between Sunni and Shia Muslims remain prevalent today, and Armstrong traces the history of those conflicts infighting over the course of the book.

Ulama are scholar-judges of Islamic law. The title can also be used for government officials of Islamic states. Armstrong highlights the development of Islamic jurisprudential infrastructure during the Abbasid Caliphate, particularly under the rule of Caliphs al-Madhi (r. 775-785) and Harun al-Rashid (r. 786-809). During this time, Ulama emerged as a distinct class of legal scholars, whose primary focus was the study of the hadiths. Over time, however, the ulama gained increasing influence over the policymaking of many Islamic governments, most notably the Seljuk Empire.