Thorfinn Karlsefn, an Icelandic explorer and wealthy trader, attempts in about 1010 to establish a settlement in the territory that Leif Eriksson called Vinland, wintering there.

Thorfinn's expeditions are documented in the Grœnlendinga saga ("Saga of the Greenlanders") and Eiríks saga rauða ("Saga of Eirik the Red"), which together are referred to as "The Vinland Sagas", but the details are at considerable variance.

According to the Grœnlendinga saga, Karlsefni left with sixty men and five women, trailing the path taken by Leif and Thorvald Eiriksson.

Whereas, according to Eric’s Saga, describing the voyage in greater detail, he took three ships with one hundred and forty men aboard.

The Scandinavian colonists, both men and women, trade and then fight with the native Skraelings (roughly, "savages").

In Greenland, Thorfinn Karlsefni had met Gudrid Thorbjorns-daughter, the widow of Thorstein Eiriksson, and wedded her.

She had been staying under the care of her brother-in-law Leif Eriksson, at Brattahlid the estate left to Leif by Eirik the Red, who was dead by this point, having succumbed to an epidemic around 1003.

Thorfinn had reached the momentous decision to go to Vinland, which according to the Grœnlendinga saga happened at the insistence of Gudrid.

And Leif agreed to lend the houses he built in Vinland, though unwilling to make a free gift of it.

Among the other settlers into Vinland was Freydis, sister or half-sister of Leif Eriksson, who may have accompanied Karlsefni's voyage (Eric’s Saga) or headed an expedition of her own that ended in carnage (Grœnlendinga Saga).

Gudrid bears Thorfinn a boy in Vinland, who is named Snorri, the first child of European descent known to have been born in the New World and to whom many Icelanders can trace their roots.

The exact location of Thorfinn's colony is unknown but is believed to potentially be the excavated Norse camp at L'Anse aux Meadows, Newfoundland.

Thorfinn Karlsefni’s brothers Helgi and Finnbogi lead additional expeditions to Vinland around 1013, but the hostility of the native Skraelings apparently causes the Scandinavians to abandon all attempts at colonization around 1015.

(Vinland could refer to L’Anse aux Meadows, or to a mainland site perhaps as far south as the Virginia Capes; scholars debate its location, as they do the locations of earlier Viking settlements.)

The colonists return to Greenland; Thorfinn eventually settles in Iceland.

This three year excursion will be the longest-lasting European colony in the New World until Columbus' voyages four hundred years later initiate full-scale colonization.