NEW YORK (NYTIMES) - Sufism is a mystical form of Islam, a school of practice that emphasises the inward search for God and shuns materialism. It has produced some of the world's most beloved literature, like the love poems of the 13th century Iranian jurist Rumi. Its modern-day adherents cherish tolerance and pluralism, qualities that in many religions unsettle extremists.
But Sufism, often known as Islamic mysticism, has come under violent attack in recent years. On Friday (Nov 24), militants stormed a Sufi mosque on the Sinai Peninsula, killing at least 235 people in what officials are calling the worst terrorist attack in Egypt's modern history.
The attack followed several assaults on Sufi shrines in Pakistan over the past year carried out by Sunni extremists. (The vast majority of Sufis are Sunni, though some are Shi'ite.)
What is this form of Islamic belief, and why has it come under assault?
THE ROOTS AND PRACTICES OF SUFISM
Sufism, known as tasawwuf in the Arabic-speaking world, is a form of Islamic mysticism that emphasises introspection and spiritual closeness with God.
While it is sometimes misunderstood as a sect of Islam, it is actually a broader style of worship that transcends sects, directing followers' attention inward.
Sufi practice focuses on the renunciation of worldly things, purification of the soul and the mystical contemplation of God's nature. Followers try to get closer to God by seeking spiritual learning known as tariqa.
Confusion about Sufism is common, even among Muslims, according to Imam Feisal Abdul Rauf, a Kuwaiti-American Sufi cleric who preached in New York City for many years and founded the Cordoba Initiative, which promotes a moderate image of Islam in the West.
"It is nothing more than the spiritual dimension" of Islam, the cleric, who goes by Imam Feisal, said in a phone interview.
"It is Islam, but we focus on meditation, on chanting sessions, which enable the Muslim to have his or her heart open. The myths people have about Sufis are analogous to the myths people have about Muslims."
For a time, beginning in the 12th century, Sufism was a mainstay of the social order for Islamic civilisation, and since that time it has spread throughout the Muslim world, and to China, West Africa and the United States. As Sufism spread, it adapted elements of local culture and belief, making it a popular practice.
Alexander D. Knysh, a professor of Islamic studies at the University of Michigan and expert in modern Sufism, describes it as a "very wide, amorphous movement" practiced within both the Sunni and Shi'ite traditions.
Sufism has shaped literature and art for centuries, and is associated with many of the most resonant pieces of Islam's "golden age," lasting from roughly the eighth through 13th centuries, including the poetry of Rumi.
In modern times, the predominant view of Sufi Islam is one of "love, peace, tolerance," Knysh explained, leading to this style of worship becoming synonymous with peace-loving Islam.
WHY EXTREMISTS HAVE TARGETED SUFIS
While some mainstream Muslims view Sufis as quirky, even eccentric, some fundamentalists and extremists see Sufism as a threat, and its adherents as heretics or apostates.
In February, militants aligned with the Islamic State attacked worshippers at the tomb of a Sufi philosopher in a remote part of southern Pakistan, killing more than 80 people, whom the militants described as polytheists. Sufis praying at the tombs of saints - a practice core to the group - have also been attacked in India and the Middle East.
The Islamic State in Iraq and Syria (ISIS) targets Sufis because it believes that only a fundamentalist form of Sunni Islam is valid.
Some fundamentalists see the reverence for saints, which is common in Shi'ite Islam, as a form of idolatry, because in their view it shows devotion to something other than the worship of a singular God.
Some consider Sufis to be apostate, because saints were not part of the original practice of Islam at the time of the Prophet Muhammad, who died in 632.
"The opponents of Sufism see the shrines and these living saints as idols," Knysh explained. "Their existence and their worship violates the main principle of Islam, which is the uniqueness of God and the uniqueness of the object of worship."
Even though Sunni hard-liners have long viewed Sufis as well as Shi'ites as heretical, terrorist networks like al-Qaeda and ISIS have debated whether killing them is justified.
The two terrorist groups have clashed over whether to focus on the "far enemy," powerful Western countries like the United States, or the "near enemy," repressive governments in the Muslim world.
Early in the Iraq War, when the ISIS' predecessor organisation targeted Iraq's Shi'ite majority, in the hopes of promoting sectarian conflict, al-Qaeda criticised the Iraqi group's leader at the time, Abu Musab al-Zarqawi, for doing so.
When a branch of al-Qaeda captured northern Mali in 2012, militants used pickaxes and bulldozers to destroy the ancient mausoleums of Sufi saints in Timbuktu.
But documents recovered in northern Mali revealed that the militants in Mali had acted without the permission of their leaders, who wrote to express their dismay, arguing that the destruction - while theologically justified - was unwise because it caused the population to turn against them.
Though al-Qaeda has also targeted Sufi sites, ISIS has set itself apart by calling for brutal attacks against Sufis.
THE STATUS OF SUFIS IN EGYPT
While no group has yet claimed responsibility for Friday's attack, it bore some of the hallmarks of previous assaults on Coptic Christians in Egypt. In the fall of 2016, ISIS' local affiliate claimed to have executed a Sufi cleric who was about 100 years old.
The religious objections of fundamentalists to the Sufi style of worship may not be the only factor behind the attacks on Sufis.
Experts say the amicable ties between Sufis and the Egyptian government may also be factor, giving the attack a political dimension. Egypt's president, Abdel-Fattah el-Sissi, who took power after the military overthrew a democratically elected Islamist president, Mohammed Morsi, has vowed to do a better job at protecting religious minorities, who were shunned when Morsi's party, the Muslim Brotherhood, was in power. By killing Sufis, the militants may be trying to undermine el-Sissi's authority.
Like its counterparts in several other Muslim-majority countries, Egypt's government supports the Sufis because it sees them as members of a moderate, manageable faction who are unlikely to engage in political activity, because their priorities are oriented inwardly.
Sufi sheikhs generally accept the legitimacy of the state, leading to tensions with Muslims who oppose their governments and are willing to act on their dissatisfaction - with violence if necessary.
"They think the society is moving in the wrong direction and Sufis are aiding and abetting the authorities on this corrupt path," Knysh said. "In ways, their reasons are very much political. They say, 'If Sufis support this, we will be against them,' more or less."
Imam Feisal said that attacks on Sufi worshippers, besides being a "major sin," are the result of the politicisation of religion in the region over the past few decades. Egypt, in particular, he said, is a place where that politicisation has fuelled extremism.
"When religion becomes politicised," Imam Feisal said, "it is not good."