Between 25 and 35 million Kurds inhabit a mountainous region straddling the borders of Turkey, Iraq, Syria, Iran and Armenia. They make up the fourth-largest ethnic group in the Middle East, but they have never obtained a permanent nation state.
In recent decades, Kurds have increasingly influenced regional developments, fighting for autonomy in Turkey and playing prominent roles in the conflicts in Iraq and Syria, where they have resisted the advance of the jihadist group, Islamic State (ISIS).
The Kurds are one of the indigenous people of the Mesopotamian plains and the highlands in what are now south-eastern Turkey, north-eastern Syria, northern Iraq, north-western Iran and south-western Armenia. Today, they form a distinctive community, united through race, culture and language, even though they have no standard dialect. They also adhere to a number of different religions and creeds, although the majority are Sunni Muslims.
In mid-2013, ISIS turned its sights on three Kurdish enclaves that bordered its territory in northern Syria. It launched repeated attacks that until mid-2014 were repelled by the Popular Protection Units (YPG) - the armed wing of the Syrian Kurdish Democratic Unity Party (PYD). The turning point was an offensive in Iraq in June that saw ISIS overrun the northern city of Mosul, routing Iraqi army divisions and seizing weaponry later moved to Syria.
The ISIS advance in Iraq also drew that country's Kurds into the conflict. The government of Iraq's semi-autonomous Kurdistan Region sent its Peshmerga forces to areas abandoned by the Iraqi army. Since then, the Kurds have been an inegral part of the West's plans to defeat ISIS.