The incredibly complex, Rubik's Cube of a political conflict known as the Syrian civil war is now stretching into its fifth year. The war has not only transformed Syria itself into a living hell; it's killed hundreds of thousands of Syrians, created millions of refugees, prompted military action from nations across the world, and fueled the rise of ISIS. But when did ISIS invade Syria to begin with?
The answer isn't exactly clear-cut. Often, it's very difficult to distinguish one Islamic terrorist group in the Middle East from another; the lines between them are frequently blurred, and sometimes, two competing terrorist organizations both claim ownership over the same sub-group. That's what happened with ISIS in Syria. The closest thing to an answer to the original question is that ISIS started moving into Syria in August 2011, as that's when the leader of ISIS sent one of his underlings to set up shop in Syria. But even that claim requires a few qualifications.
First of all, ISIS hasn't always been ISIS. The group was originally the Iraqi branch of al Qaeda — it used to be called al Qaeda in Iraq, or AQI — and for years, that was the only country in which it operated. But in August 2011, after the civil war in Syria started tearing the country apart, AQI started expanding there. The group's leader, Abu Bakr al-Baghdadi, sent one of his subordinates to Syria to establish a foothold in that country. That foothold took the form of an extremist group called the al Nusra Front — and from here, the record gets a bit hazy. Bear with me here.
In 2013, AQI split off from al Qaeda and rebranded itself ISIS. Shortly after that, Baghdadi announced that the al Nusra Front was part of ISIS. But the leader of al Nusra denied this; he said that his group was actually allegiant to al Qaeda, which was (and still is) a rival of ISIS. Al Qaeda soon weighed in on the issue, and its leadership confirmed that yes, al Nusra was indeed the Syrian branch of al Qaeda. But Baghdadi denied this, and continued claiming that al Nusra was part of ISIS.
Ultimately, al Nusra split into two, with some fighters siding with al Qaeda and others siding with ISIS.