The practice of granting asylum to people fleeing persecution in foreign lands is one of the earliest hallmarks of civilization. References to it have been found in texts written 3,500 years ago, during the blossoming of the great early empires in the Middle East such as the Hittites, Babylonians, Assyrians and ancient Egyptians.
Over three millennia later, protecting refugees was made the core mandate of the UN refugee agency, which was set up to look after refugees, specifically those waiting to return home at the end of World War II.
The 1951 Refugee Convention establishing UNHCR spells out that a refugee is someone who "owing to a well-founded fear of being persecuted for reasons of race, religion, nationality, membership of a particular social group or political opinion, is outside the country of his nationality, and is unable to, or owing to such fear, is unwilling to avail himself of the protection of that country."
Since then, UNHCR has offered protection and assistance to tens of millions of refugees, finding durable solutions for many of them. Global migration patterns have become increasingly complex in modern times, involving not just refugees, but also millions of economic migrants. But refugees and migrants, even if they often travel in the same way, are fundamentally different, and for that reason are treated very differently under modern international law.
Migrants, especially economic migrants, choose to move in order to improve the future prospects of themselves and their families. Refugees have to move if they are to save their lives or preserve their freedom. They have no protection from their own state - indeed it is often their own government that is threatening to persecute them. If other countries do not let them in, and do not help them once they are in, then they may be condemning them to death - or to an intolerable life in the shadows, without sustenance and without rights.