A study published Wednesday revealed the exact date Vikings arrived in North America.

Authors of the study analyzed tree rings at L’Anse aux Meadows, a UNESCO world heritage site in Newfoundland, Canada, and determined that Vikings were already present in North America in 1021 AD, more than four centuries before Christopher Columbus.

The scientists made use of a known solar storm that took place 992 AD and its effect on the rings of three trees cut at the camp. In all of the samples, only 28 growth rings were formed after the one that was affected by the storm, meaning the “exact felling year of the tree” was 1021 AD, the study said.

A study in Nature suggests that Vikings may have occupied the Americas as early as 1021 AD, 1,000 years ago. Radiocarbon dating of artefacts discovered in Canada reveal what may be the earliest known record of humans crossing from Europe to the Americas. https://t.co/tJKksExUe4 pic.twitter.com/AEKjfx8C2t

— nature (@Nature) October 21, 2021

While previous studies based on a stylistic analysis of a handful of artefacts and the architectural remains of the site enabled scientists to arrive at a rough estimate of Vikings’ arrival, the exact date was never known.

A number of school boards across the U.S. have replaced Columbus Day, which still remains a federal holiday, with Indigenous People’s Day. (RELATED: DeSantis Blasts Those Who ‘Seek To Defame’ Christopher Columbus By Revising History)

“Italian Heritage/Indigenous People’s Day will celebrate the contributions and legacies of Italian Americans and recognize Native people are the first inhabitants of the land that became our country,” New York City Department of Education (NYCDOE) said of its early May decision to rename the holiday. “By including these holidays on our calendar we are honoring the past, present, and future contributions of Indigenous communities and Italian Americans.”