Around four millennia ago, the Xia dynasty – China’s first line of unbroken hereditary rulers – was born along the Yellow River, according to legendary texts. Save for some mysterious stone carvings and possible tombs, though, there’s very little archaeological evidence that convincingly shows that the Xia dynasty ever existed.

It is, however, immortalized in the tale of the Great Flood. This epic story describes how a huge natural disaster almost destroyed the region before a man named Yu stepped in to save the day. According to legend, an immense flood 4,000 years ago left a portion of China on the brink of ruin, but, supposedly, Yu managed to divert much of the floodwater away from major settlements.

Many have thought that this was nothing more than an elaborate work of fiction, but a striking new study published in Science reveals that the Great Flood was almost certainly a historical fact.

An international team of researchers were carefully mapping ancient sediments along the Yellow River when they stumbled across something shocking. The sedimentological records indicated that a powerful flood did indeed inundate the land thousands of years ago, and it would have certainly looked like the end of the world to anyone caught in its fury.

“This was one of the largest floods to have happened on Earth in the last 10,000 years,” study co-author Darryl Granger, professor in the department of earth atmospheric planetary sciences at Purdue University, said in a press conference. The flood was likely to have destroyed settlements as far as 2,000 kilometers (1,240 miles) downstream.

Using radiocarbon dating on a series of skeletons, ones belonging to people killed by the earthquake and then buried by the flood, they determined that it occurred in the year 1920 BCE, right at the time that written legends say the Xia dynasty came into being.

Image in text: Rough location of the Xia dynasty. Gurdjieff/Wikimedia Commons; CC BY-SA 3.0

Some of the skeletons at the key Lajia archaeological site. Cai Linhai

Earlier that year, a powerful earthquake shook the region, and the team’s evidence shows that a huge landslide blocked the upper section of the Yellow River. This natural dam, roughly a third of the size of the Empire State Building, accumulated water over nine months, before catastrophically bursting.

This geological evidence matches up incredibly well with the story of the flood described in ancient apocryphal Chinese texts, which strongly suggests that the revered myth was true all along. So was the Xia dynasty, the nucleus of Chinese civilization, more fact than fiction as well?

The Hukou Waterfall of the Yellow River. Leruswing/Wikimedia Commons; CC BY-SA 3.0