Modern humans began to edge out the Neanderthals in Europe earlier than previously thought, a new study shows.
Tests on remains from a cave in northern Bulgaria suggest Homo sapiens was there as early as 46,000 years ago.
This is up to 2,000 years older than evidence from Italy and the UK.
Around this time, Europe was populated by sparse groups of Neanderthals - a distinct type of human that vanished shortly after modern humans appeared on the scene.
There's considerable debate about the length of time that modern humans overlapped with Neanderthals in Europe and other parts of Eurasia.
This has implications for the nature of contact between the two groups - and perhaps clues to why Neanderthals went extinct.