Scientists have made a remarkable discovery about Europeans from the Ice Age — a discovery that could forever shape how we understand how modern man came to migrate across the continent.

After an analysis of DNA from ancient bones dated between 45,000 and 7,000 years old, a team of international scientists have found that the demographic history of early Europeans was far more dynamic than previously thought, and that they all lived in the area of Belgium many years ago while living alongside our extinct cousins, the Neanderthals, according to a Howard Hughes Medical Institute statement.

The researchers examined DNA from 51 prehistoric humans and found that all specimens younger than 37,000 years old appeared to have descended from a single population.

Modern humans had arrived in Europe about 45,000 years ago, but scientists hadn’t understood very well exactly how they spread across the continent — this study sheds tremendous light on that.

This one particular group lived in the region of modern-day Belgium about 35,000 years ago and is believed to have directly contributed to the ancestry of modern-day Europeans. They are believed to have resulted in the demise of the Neanderthals, despite some interbreeding.

“The new genetic data, published May 2, 2016 in Nature, reveal two big changes in prehistoric human populations that are closely linked to the end of the last Ice Age around 19,000 years ago,” the statement reads. “As the ice sheet retreated, Europe was repopulated by prehistoric humans from southwest Europe (e.g., Spain). Then, in a second event about 14,000 years ago, populations from the southeast (e.g., Turkey, Greece) spread into Europe, displacing the first group of humans.

“Archeological studies have shown that modern humans swept into Europe about 45,000 years ago and caused the demise of the Neanderthals, indicated by the disappearance of Neanderthal tools in the archaeological record,” it continues. “The researchers also knew that during the Ice Age — a long period of time that ended about 12,000 years ago, with its peak intensity between 25,000 and 19,000 years ago — glaciers covered Scandinavia and northern Europe all the way to northern France. As the ice sheets retreated beginning 19,000 years ago, prehistoric humans spread back into northern Europe.