A mystery which has intrigued historians for more than 400 years - the fate of Sir Walter Raleigh's "lost colony" of Roanoke - may at last have been solved by archaeologists who think the colonists were the victims of drought.
For centuries, scholars have been baffled by the complete disappearance of the 120-strong Elizabethan-era colony, which was the first English settlement in North America as well as the birthplace of the first European baby to be born on the American continent, Virginia Dare.
However, new research from the study of the rings of centuries-old cypress trees in the Roanoke region has revealed that the pioneer colonists had the misfortune to be carving out their toehold in the New World at the peak of the worst drought in the region's history. The fluctuating ring patterns of the cypresses, which commonly live for 800 years or more, revealed evidence of a ferocious three-year dry spell between 1586 and 1588.
"It wasn't just a drought, it was an amazing drought," said Prof Dennis Blanton of Virginia's William and Mary College, who co-authored the new study.
"We're still not in a position to explain the mystery of the famous disappearance, but we may now know more about the situation that led to it."
Two teams, from William and Mary and the University of Arkansas, said the droughts also probably caused the extreme hardships suffered by colonists at nearby Jamestown. Writing in the journal Science, they said it would have been hard for anyone to survive during the drought, let alone colonists new to the area.
Raleigh's colonists began building their community on Roanoke Island, off the coast of present-day North Carolina, in 1587, with the support of Queen Elizabeth I. Later that year, a group of colonists set sail back across the Atlantic to fetch fresh supplies and bring more settlers. But they arrived in England just as all ships were being requisitioned to repel the expected Spanish Armada, and as a result they were unable to return to Roanoke until 1590.
When they finally returned, they found the Roanoke site deserted and no trace of the 120 settlers, including Virginia Dare, whom they had left behind. The only clue was the celebrated but enigmatic carving on a nearby tree of the single word "Croatoan".
Historians have long debated the fate of the Roanoke settlers, and the story, which is widely taught in American schools, attracts thousands of visitors to the island each year. Fortunately for Roanoke's thriving "lost colony" tourism industry, the archaeologists' new findings still leave many aspects of the mystery unanswered.
The drought theory increases the likelihood that the Roanoke settlers were forced to abandon the island when their crops failed and they were unable to trade with local Indian tribes, who would also have been suffering. Whether the settlers were massacred - as early anti-Indian theories assumed - or whether they tried to journey up the coast in search of a more hospitable site - as later versions have suggested - may never be known. A third possibility, still promoted by the Lumbee Indians of North Carolina, is that the starving English threw in their lot with the Indians and intermarried with them.
The research also shows that a second drought, lasting from 1606 to 1612, almost brought about a similar disaster for English colonists at Jamestown in present-day Virginia, which became England's new American foothold after the disappearance of the Roanoke settlers. Four-fifths of the Jamestown settlers died between 1607 and 1625, with malnutrition a leading cause.