President Joe Biden delivered an apology Friday for a United States policy that forcibly separated generations of indigenous children from their families for more than 150 years and sent them to federally backed boarding schools for forced assimilation.

“I formally apologize as president of the United States of America for what we did,” Biden said in strident remarks. “It’s long overdue.”

The president’s apology comes in the wake of a years-long investigation commissioned by Interior Secretary Deb Haaland, a member of the Pueblo of Laguna and the first Native American to serve as a Cabinet secretary. Haaland’s grandparents were separated from their families because of the policy.