WE KNEW THIS BEFORE, BUT THE DATING IS MUCH MORE PRECISE NOW: In tree rings and radioactive carbon, signs of the Vikings in North America.

Scientists have known for many years that Vikings — a name given to the Norse by the English they raided — built a village at L’Anse aux Meadows in Newfoundland around the turn of the millennium. But a study published in Nature is the first to pinpoint the date of the Norse occupation.

The explorers — up to 100 people, both women and men — felled trees to build the village and to repair their ships, and the new study fixes a date they were there by showing they cut down at least three trees in the year 1021 — at least 470 years before Christopher Columbus reached the Bahamas in 1492. . . . But their stay didn’t last long. The research suggests the Norse lived at L’Anse aux Meadows for three to 13 years before they abandoned the village and returned to Greenland.

What Columbus did that the Vikings didn’t, though, was open up the New World to a system of global commerce.