Where the Romani people came from was argued over for centuries, and it was settled by linguistics. In the late eighteenth century scholars noticed that Romani vocabulary corresponded to Indo-Aryan, and the correspondence has since been worked out in detail: Romani is an Indo-Aryan language, its inherited stock points to northern India, and the layers of borrowing it picked up on the way, Persian, Armenian and above all Greek, trace a route westward. That is a rare case of a people's origin being recovered from grammar after the historical record had failed.
Romani communities are attested in the Byzantine world and then across Europe from around the fourteenth century, and today they include the Roma of central and eastern Europe, the Sinti of German-speaking lands, the Kale of Iberia and of Finland and the Romanichal of Britain, with considerable variation in language, occupation and religion.
The English word Gypsy rests on a mistaken medieval belief that they came from Egypt. It is rejected by many and reclaimed by some, and there is no single term that everyone accepts. The twentieth century added a second reason to record this accurately. Between a quarter and half a million Romani people were murdered in the Nazi genocide, the Porajmos, and recognition of it came late and grudgingly in most of the countries where it happened.