Dr. James R. Schlesinger — the first person to ever serve as U.S. Secretary of Energy — passed away on March 27, 2014.

Known as the “father of the Energy Department,” Schlesinger was tasked by President Jimmy Carter with organizing various smaller agencies — including 40 field offices and about 20,000 employees — into the Energy Department that grew into what exists today.

Check out the gallery of photos, from the Energy Department archives, to look back at Schlesinger’s legacy and accomplishments.