The appalling atrocities and killings by the Islamic militants may seem "unprecedented in the modern age" but a Cambridge scholar is drawing parallels between the group and the rise and fall of an extremist group, Tawheed, in Lebanon in the 1980s.
Tawheed seized control of the northern port city of Tripoli and imposed its conservative agenda on locals, before being largely rejected and marginalised by civil society and leftist militants.
"While it's important to keep in mind that history does not necessarily repeat itself, the parallels are great between the history of the rise and fall of Tawheed's emirate in Tripoli and the current rule of the Islamic State," says Raphaël Lefèvre, a Gates Cambridge Scholar working in the Department of Politics and International Studies.
While in its practice of extremism Islamic State (Isis) has few precedents, Lefèvre believes a similar pattern of emergence of both groups gives a pointer to the future path of IS.
"It is unpopular in the cities it is controlling, but we are not yet seeing so much resistance – possibly because of the socioeconomic help they currently provide. While the same collapse may not necessarily happen to IS, the rise and fall of Tawheed shows that internal tensions within a group are an important factor that should be taken into account to understand how such movements operate. The 'IS phenomenon' is in fact far from being a new one."
Tawheed gained control at a time of civil unrest, filling the socioeconomic gap left by the absence of a Lebanese state. "They filled a void – provided security, ran hospitals and even gave education to the kids," he explains.
It lost legitimacy when it began to be perceived as a militia using a religious discourse to mobilise people.
How they collapse
Lefèvre believes that movements collapse when they try to force society to adapt to their norms: "Very often, civil society resists and in the end strikes back."
Street violence is rising, sectarianism is reaching boiling point and IS has now inaugurated a Lebanese chapter in Tripoli, he notes.
Like Tawheed, IS has both imposed a harsh conservative social agenda on the population who live under its sway and is using resources such as oil and gas fields to win over locals.
"They distribute subsidies and provide state-like services to a population in severe need given the quasi-absence of the Syrian state in remote areas outside of Damascus."
Just like IS, Tripoli's Tawheed movement was led by a charismatic figure, the Sunni cleric Said Shaaban.
He gathered under his wing three Islamist groups that merged together to form Tawheed. Their aim was to struggle against impurities in society in accordance with Sharia law.
"But, once Tawheed seized control of the city in 1983, all of these grand goals very quickly disappeared. People started realising that there wasn't much that was Islamic about the group; it was just another political faction trying to rule their city instead of Syria and Israel, and in increasingly corrupt and murky ways."
After three years, and in the face of pressure from the Syrian regime, internal disagreements over deciding the group's next steps led to its collapse from within.
IS, too, has been linked with corruption, he notes, pointing to the way the group has been selling looted stuff and oil supplies to the Syrian government and across the borders into Turkish and Jordanian underworlds.
He also hopes that his research on the events of the 1980s in Lebanon will focus attention on the roots of an increasingly unstable situation in the country.