The picturesque and remote Faroe Islands sit in the North Atlantic, between Norway and Iceland, around 200 miles (322 kilometers) northwest of Scotland. Today, almost 54,000 people live on the archipelago, but it seems the first inhabitants arrived a lot earlier than previously thought.

From the earliest archaeological structures on the Faroes, we know that Viking explorers stopped off on the islands around 800-900 CE. Now there's new evidence that human inhabitants were around some 300 years earlier than that.

Through a study of lake sediment dated to around 500 CE, researchers have spotted signs that sheep were grazing on the Faroe Islands at that time, sheep that could only have arrived with people. Researchers discovered sheep DNA along with two lipids that are produced in the digestive systems of sheep.

"We see this as putting the nail in the coffin that people were there before the Vikings," says paleoclimatologist and the study's lead author Lorelei Curtin. Curtin performed the research while at the Lamont-Doherty Earth Observatory at Columbia University in New York.

A layer of ash in the sediments, linked to an Icelandic volcano eruption in 877 CE, helped the team be more sure about the timeline they were looking at – and that sheep (and their farmers) had somehow found their way to the Faroes before the Norse visitors.

As yet, no evidence of human populations pre-dating the Vikings has been found on the Faroes, but this isn't particularly surprising as there aren't many spots on the island flat enough for settlements, so it's likely that any structures that existed before 800 CE were then later built over. Indeed, the Norse used the island as a summer settlement for grazing sheep sometime in the 9th century, and they eventually abandoned it in the mid-11th century.

This research, however, is the most conclusive evidence yet that people came to the Faroes before the Vikings. It's not the first time the idea has been put forward: Weeds associated with pastures and human farming can be traced back for thousands of years on the Faroes, though of course, the wind can carry seeds to new locations.

There are also several historical documents written by monks talking about northern islands inhabited way before 800 CE. These islands may in fact be the Faroes, but from the clues we have, it's difficult to know for sure. Now, there's solid evidence in the solid sediment extracted from a lake near the village of Eiði, on the island of Eysturoy.

"Those early writings are tenuous – it's all circumstantial," says paleoclimatologist William D'Andrea, from the Lamont-Doherty Earth Observatory. "You see the sheep DNA and the biomarkers start all at once. It's like an off-on switch."

It's not clear who these early settlers might have been, though the researchers raise the possibility that they were Celts. Many Faroese places are named after Celtic words, while ancient Celtic grave markings can be found on the island – though it's hard to date them.

Before now, the most substantial evidence that anyone arrived on the Faroes before the Vikings was a 2013 study analyzing charred barley grains from under the floor of a Viking longhouse – barley grains dated to around 300-500 years before the Norse settlers turned up, which could only have been brought by human hand. The discovery of sheep on the islands adds more weight to this timeline.

Archaeologist and environment researcher Kevin Edwards, from the University of Aberdeen, worked on the 2013 paper and says that the research techniques used in this latest study could be deployed elsewhere to look for earlier human settlements.

"Is similar evidence to be found in Iceland, where similar arguments are made for a pre-Norse presence, and for which tantalizingly similar archaeological, pollen-analytical, and human DNA are forthcoming?" says Edwards.

The research has been published in Communications Earth & Environment.