Top 10 Leaders of Religious Violence

In the history of religious violence, some have stood out and made a name for themselves as the most influential and effective purveyors of oppression and hatred. Here are the top ten of all time, in chronological order.

Theodosius I, or Theodosius the Great, was the last emperor of the united Roman empire. He reigned from 379 to 395, and effectively made Nicene Christianity the official religion of the empire. He persecuted pagans and non-Nicene Christian groups, including the Arians. He established the death penalty for certain pagan practices, made private pagan worship illegal in some cases, destroyed a number of pagan temples and abolished their holidays. Theodosius also succeeded in battle against the forces of the pagan Eugenius, who sought the throne. He is recognized as a Saint by the Eastern Orthodox.

Muhammad (570-632) was the founder and prophet of Islam, and the first political and military leader of the Islamic community. Believing that it was God's mission for him to convert and conquer for Islam, he organized fighters early on to resist persecution from polytheistic Arabs, and then to establish sovereignty over them.

The Islamic empire conquered the entire Arabian peninsula under Muhammad, and subsequent caliphs expanded its dominion over the entire Middle East, Southwest Asia, Northern Africa and Iberia. Muhammad established political, religious and even cultural norms that remained in place for many centuries across large segments of Africa and Asia.

The Quran, Islam's holy book, includes many verses supportive of violence, persecution and oppression. These ideas were inspired directly by Muhammad's militant activities and the violent world that he and his earliest followers were a part of. The justification and exaltation of violence in various elements of Islam continue to inspire militant Muslims to this day.

Pope Urban II established the First Crusade (1096-1099) in an attempt to support Christians in Anatolia in their conflict against Muslim armies, and also to recapture the Holy Land from Muslim control. Jerusalem had not been under Christian control for over 400 years.

Thousands of men from around Europe participated in the Crusade. The Christian zeal stirred up by Urban and his supporters had the unintended consequence of mob killings of Jews in France and Germany, as Crusaders and prospective Crusaders travelled east. Many Crusaders never made it out of Europe. Those that did reach the Levant successfully expelled the Muslims and established several Christian states. In the process, an unknown number of Muslims and Jews were massacred by the Crusading armies.

Urban's crusading legacy remained in place as eight more Crusades followed in subsequent centuries, some begun by popes and others by monarchs. The chaotic and undisciplined nature of a transcontinental religious adventure, undertaken largely by illiterate peasants fired up with radical rhetoric, remained a distinguishing feature of the Crusades.

Urban's Crusade, and the later Crusades, bolstered tensions between Muslims and Christians that arguably continue to this day.

Pope Gregory IX founded the Papal Inquisition in 1231 (not to be confused with the Spanish Inquisition of several hundred years later). The Papal Inquisition was an attempt to better organize, systematize and centralize existing Inquisition activities. An Inquisition, in all its manifestations, was a procedure designed to identify and punish or rectify those holding beliefs heretical to official Catholic doctrine.

A variety of punishments were used for those convicted of heresy, ranging in severity from prayer to social ostracism to flogging to death. Since the church itself could not harm anyone, Gregory and subsequent popes employed secular authorities to torture and execute suspects and convicted heretics. Those who were executed were typically burned at the stake. The inquisitional procedures and standards established by Gregory remained in force for centuries thereafter.

Archdeacon of Ecija, a town near Seville, Martinez made a name for himself incessantly preaching against Jews in the late 14th century. Despite requests to stop from political leaders (who benefited from Jewish contributions in medicine, law and other fields), Martinez was steadfast in his violent rhetoric, calling for Jews to be killed or baptized.

Finally, in the massacre of 1391, somewhere between 2,000 and 10,000 Jews were killed by mobs inspired or led by Martinez and his clerical allies. The mass killings began in Seville, but soon spread to other Spanish cities in an environment of near-anarchy with incompetent secular authorities unable to protect the innocent. Many Jews opted to convert to Christianity. However, suspicion of heretical activities by recent Jewish converts contributed to the establishment of the Spanish Inquisition about 100 years later.

In the closing years of the 15th century, Tomás de Torquemada led the effort in establishing the Spanish Inquisition. He became Spain's first Grand Inquisitor, and significantly increased the size, organization and discipline of the Inquisition. Between 1480 and 1530 the Spanish Inquisition burned about 2,000 people at the stake. While Torquemada was in charge for only the early part of this period, he was essential in developing its zeal and effectiveness. Almost all of those executed were Jewish converts to Christianity.

The Spanish Inquisition continued at a slower rate for several centuries afterward, trying tens of thousands more people and killing several thousand. Torquemada's name has become synonymous with religious hatred, bigotry and fanaticism.

John Calvin was one of the most consequential Protestant reformers. As a reformer in mid 16th century Geneva, he successfully implemented a theocracy in which church leaders (including Calvin) enjoyed political and legal authority. His rule saw the imposition of a strict moral code based on a literal interpretation of the Bible.

Laws and punishments directly inspired by the Old Testament were a feature of Calvinist Geneva, including the death penalty for adultery. Calvin considered adultery in particular to be a crime worse than robbery. Calvin implemented public torture or banishment for crimes including heresy and nastiness on the part of children. Dancing, theater performances and singing (even in church) were all ultimately banned. Several children and teenagers were executed or brutally punished for nonviolent offenses. In one famous case, Michael Servetus, a well-known European thinker and critic of the doctrine of the Trinity, was tried, convicted of heresy, and burned to death.

Calvin's greatest impact was felt beyond Geneva in later decades and centuries. His rigid ideas influenced puritanical Protestants in continental Europe, England and the early United States.

In the mid 19th century, Hong Xiuquan had visions convincing him that he was the brother of Jesus Christ, and that God wanted him to establish a Christian state in China. With his army of followers, he led the Taiping Rebellion (1850-1864) against the ruling Qing dynasty. The conflict grew from a guerilla rebellion to a full-scale civil war that killed about 20 million people. Hong succeeded in conquering a section of southern China before the Qing and its foreign allies ultimately triumphed. The Taiping Rebellion was one of the largest wars of the 19th century by number of soldiers and number of deaths.

While in power, Hong acted as both political and religious leader of the "Heavenly Kingdom," implementing laws including segregation of the genders, land socialization, outlawing polygamy (despite Hong's own harem of concubines), outlawing gambling and prostitution, and the suppression or destruction of Confucian and Buddhist symbols and practices. Brutal and uneven military rule was used to enforce the theocracy's policies.

The Grand Ayatollah Khomeini was the leader of the Iranian Revolution (1979) that overthrew the American-backed regime and established a Shiite Muslim theocracy. Khomeini ruled as Supreme Leader for ten years until his death.

Khomeini was one of the primary forces behind large-scale anti-Americanism as well as a movement toward greater piety and traditionalism in the late 20th century Muslim world. Under Khomeini, political dissent was suppressed, thousands of political prisoners were executed, and while Jews and other non-Muslims were treated relatively well, the Bahai were actively persecuted.

Under Khomeini, alcohol, western movies, non-religious and non-martial music were all banned. Sports and beaches were gender-segregated, women were forced to cover their hair, and men were banned from wearing shorts.

Khomeini's rigid and violent beliefs continue to shape Iranian policy. Extramarital sex is illegal in Iran, women can be punished if found in mixed-sex situations, and violent punishments often apply for sexual indiscretions, including death. Women are punished more often than men, while enjoying fewer rights. In 2010, a woman was sentenced to death by stoning for the crime of adultery. The ruling was later tempered amid an international outcry.

Osama bin Laden was the world's most prominent Islamic terrorist in the late 20th and early 21st century. As the head of the global Islamist group Al Qaeda, he was an inspiration and a symbolic leader to thousands of fanatical Muslims. He was the architect of the September 11th, 2001 attacks on New York City and Washington DC that killed about 3,000 people. The September 11th attacks were the spark for the American "war on terror," an ongoing global military, police and intelligence campaign against Islamic terrorists. This campaign ultimately resulted in bin Laden's death at the hands of an American special forces unit in May 2011, almost ten years after his most important attack.

After adopting a fundamentalist belief system, bin Laden made a name for himself in the 1970s and 80s as a military leader for the Mujahideen (conservative Islamic fighters) in the American-backed conflict against the Soviet Union in Afghanistan. His battlefield experience, arms networks and vast financial resources readily applied to Al Qaeda's terrorist activities in the 1990s and 2000s.

Muhammad Amin al Huseini: Grand Mufti of Jerusalem for much of the 20th century; loved Nazis, hated Jews; called for the killing of Jews.

Mullah Muhammad Omar: Spiritual and military leader of the Taliban; banned music and entertainment, implemented draconian punishments, banned women from work and education.

Joseph Kony: Leader of a religious terrorist group in Uganda whose anti-government war has killed tens of thousands and displaced 2 million; forces have engaged in child abduction, torture, child rape, slavery and murder; has fathered dozens of children with between 20 and 70 wives--many of them young girls.