David Thomson should be more famous.

After all, he was the first European settler to come to New Hampshire—hired, in fact, by the very same company that hired the Pilgrims to come to America three years earlier in search of commerce and opportunity.

But history isn’t always fair, or kind, or even entirely accurate. And the 400-year-old facts of David Thomson’s life are a bit skimpy. He also had the disadvantage, at least in the eyes of presidents and historians, of coming to America to make money, not for religious freedom. So his story lacked the romance or heartwarming narrative of the Pilgrims’s story. He also disappeared shortly after he arrived here under mysterious circumstances.

Here’s what we know. Thomson and his wife Amias, came with a group of fisherman to settle New Hampshire in 1623. There’s evidence that he came to the New England Colonies as early as 1607 as part of the Popham Colony in Maine. In 1626, Thomson became one of the first Europeans to settle Boston (Thomson Island, where he moved his family, is named in his honor), but after 1628 he disappeared without a trace. Foul play? Tragic accident? Historians have guesses, but we may never know.

In 1899, the Colonial Dames of NH established a monument to Thomson (though his name doesn’t actually appear on it) and the first NH settlers on a bluff overlooking the ocean. In 1955, the 8,000 pound monument was moved by the Air Force to nearby Odiorne Cemetery, but was returned to its original bluff in Odiorne State Park in 2007, where it continues to be maintained by the Colonial Dames. Historian Charles Brewster, writing in the early 1800s, said “Odiorne’s Point should be respected as our Plymouth Rock.”

So this modest marker may in fact commemorate one of the most significant events—and influential settlers—in American history. History is still deciding.