When a mosque in Egypt’s Sinai region was attacked by affiliates of the Islamic State armed group in November leaving over 300 people dead the attackers said they were targeting what they described as 'heretics of Islam', known to the wider world as Sufis.Who are the Sufis and why have they been singled-out by some other Muslims? The term ‘Sufi’, will, for many, conjur up images of poets like the Persian Jalāl ad-Dīn Muhammad Rūmī from the 13th century, or the Abū 'Abdillāh Muḥammad ibn 'Alī ibn Muḥammad ibn `Arabī from Andalusia in Spain from the 12th century, or even Turkey’s whirling dervishes. While poetry and dervishes can be part of different Sufi orders, at the heart of Sufism, is Islam, and its interaction with the prophet Mohammed. Sufis, however, have always differed because they have evolved and adapted their practice of Islam. According to Hamza Malik, a lecturer in Sufism at the department of the Near-and-Middle-East at SOAS, University of London, Sufism strarted to distinguish itself from mainstream Islam in the 1800s. Malik explains that those studying Sufism often sought something that didn’t resemble the strict interpretation of Islam, but instead included some elements closer to Christianity. Such differences become more apparent during the wave of colonization in the 19th century. It's at this point that Muslims began to question where they had gone wrong since they were losing control of their lands. "The answer generally lay in [the fact that] they had moved away from [the] original teachings of Islam” explains Malik. 21st century Sufis Getting a true number of practicing Sufis is hard to come by, since it depends on the order and how one defines a Sufi. In fact, many do not consider themselves Muslim. One article by Stephen Schwartz, a practicing Sufi himself, says out of the roughly 1.3 billion Muslims worldwide, five percent are Sufis. But much of the confusion in defining Sufis as Muslims stems from the fact that Sufism evolved differently than mainstream Islam. Malik explains that this willingness to look deeper into the “spiritual essence of Islam” rather than just its literal adherence to routine, is what attracted people. Different Sufi communities follow different Sufi orders. The orders are based on individual Sufis in history who inspired followers. Rabia and Hasan are two practicing Sufis who grew up in the United States as Presbyterian Christians, but later converted to Sufism. They practice the Sufism developed by Hazrat Inayat Khan, an Indian musician who worked in the early twentieth century. “He [Hazarat] was a court musician in India and was also a Sufi. This was [in] 1910, and he believed very strongly that Islam and Hinduism and [other religions] and Christianity were all facets of the same thing” explains Hasan. “They were all trying to reach something deeper. So he felt that you didn't have to be a Muslim, or a Hindu as such. You weren't being locked into one thing.” Not being locked into one thing is why Sufism was never about a religion, adds Rabia. “Sufism was never a religion. Islam is a religion.” Sufism and Islam But most specialists disagree and insist that Sufism comes from Islam and the Koran. Hisham Hellyer is a senior non-resident fellow at the Atlantic council and a professor at the Centre for advanced study of Islam, science and civilization in Malaysia. He says the two cannot be separated because he believes it's “historically not true”. He adds: “Very basic practice of all Sufis is to read the Koran and that's the Islamic revelation part par excellence and to imagine that is something that can be separated from Islam, I'm not sure how you can do that." But for hundreds of thousands of people around the world, Sufism has become a means of achieving a spirituality that is rooted in Islam, but that is not necessarily part of