East-to-west human dispersal into Europe 1.4 million years ago.

Stone tools stratified in alluvium and loess at Korolevo, western Ukraine, have been studied by several research groups 1-3 since the discovery of the site in the 1970s. Although Korolevo's importance to the European Palaeolithic is widely acknowledged, age constraints on the lowermost lithic artefacts have yet to be determined conclusively. Here, using two methods of burial dating with cosmogenic nuclides 4,5 , we report ages of 1.42 ± 0.10 million years and 1.42 ± 0.28 million years for the sedimentary unit that contains Mode-1-type lithic artefacts. Korolevo represents, to our knowledge, the earliest securely dated hominin presence in Europe, and bridges the spatial and temporal gap between the Caucasus (around 1.85-1.78 million years ago) 6 and southwestern Europe (around 1.2-1.1 million years ago) 7,8 . Our findings advance the hypothesis that Europe was colonized from the east, and our analysis of habitat suitability 9 suggests that early hominins exploited warm interglacial periods to disperse into higher latitudes and relatively continental sites-such as Korolevo-well before the Middle Pleistocene Transition.