On August 18, 1590, John White rowed ashore on Roanoke Island looking for his family.

He had been gone three years. When he'd left, his daughter Eleanor had just given birth to a baby girl, Virginia Dare—the first English child born in the Americas. That day, August 18, was Virginia's third birthday.

The sailors with him had seen smoke rising from the island the night before. They'd blown a trumpet and sung English songs into the dark so whoever was there would know they were friends. No one answered.

In the morning they found the settlement. The houses had been taken down. A tall wooden palisade had been built around the site. On one of its posts, someone had carved a single word in capital letters:

CROATOAN

Why they were there

England had tried Roanoke Island once already. In 1585, a mostly military expedition under Ralph Lane built a fort there. Supplies ran short, relations with the local Algonquian peoples turned violent, and in 1586 the men abandoned it and caught a ride home with Sir Francis Drake.

The 1587 colony was different. It was families. About 115 men, women and children sailed under John White, an artist who had been on an earlier voyage and painted some of the most important early images of the people and plants of the region. The plan was to settle on the Chesapeake Bay, farther north. But the ships' pilot, Simon Fernandes, put them ashore at Roanoke and refused to take them farther.

Virginia Dare was born on August 18, 1587. A few days later the colonists persuaded White to sail back to England himself and bring supplies. He didn't want to go. He went.

Three years away

White reached England just as war with Spain was building. In 1588, as the Spanish Armada approached, ships that could have carried him back across the Atlantic were held for England's defense. A small attempt to return failed. It took until 1590 for White to get back.

Before he'd left, he and the colonists had agreed on a signal. If they moved, they would carve the name of where they had gone. If they were in trouble, they would carve a cross above it.

There was no cross.

On a tree nearby, White found three letters: CRO. On the palisade post, the full word. Chests had been dug up and broken open—some of them his. His books, maps and paintings were ruined by the rain.

Croatoan was the name of an island to the south, part of today's Hatteras area, and of the people who lived there. One of the colony's allies, a Croatoan man named Manteo, had traveled to England and back with the English. White took the carving as good news. His people had gone to friends.

He never reached them. A storm came up, an anchor was lost, and the ship's crew refused to go on searching. They turned for home. John White never returned to America.

What happened to them

There's no single answer, but there are real leads.

They went to Croatoan. It's what the carving says. Since the late 2000s, archaeologists working on Hatteras Island have reported finding 16th-century English objects at Croatoan village sites. Critics argue those items could have arrived through trade rather than settlers. It's the most direct reading of the evidence, but not proven.

They went inland. In 2012, researchers studying White's own map at the British Museum found a patch hiding a symbol at the head of the Albemarle Sound. The First Colony Foundation has since excavated near Merry Hill, in Bertie County, and reported English pottery. Some have argued a group moved there.

They were killed. Years later, the Jamestown colonists heard reports that survivors of Roanoke had been living with or near Native peoples before being killed. Those reports are secondhand and their details don't line up.

They split up. Many historians suspect the colonists didn't do any one thing. A hundred people could have divided—some to Croatoan, some inland—and been absorbed into Native communities over the following years.

One thing can be ruled out. In 1937, a stone appeared claiming to be a message from Eleanor Dare. Dozens more "Dare Stones" followed. They were exposed as forgeries.

What's known and what isn't

Documented: About 115 colonists landing in 1587; Virginia Dare's birth on August 18, 1587; White's departure; his return on August 18, 1590; the CRO and CROATOAN carvings; the agreed-upon cross that wasn't there.

Unknown: Where the colonists went, how many survived, and what became of Virginia Dare.

It's been more than 400 years. The word on the post is still the best clue anyone has—and it might simply have been telling the truth.

Watch the Short below, then tell us which theory you think fits the evidence best.