Boxing champion Muhammad Ali was always a captivating figure. Perhaps nowhere are his undeniable strength and charisma captured than in the photography of Gordon Parks, who shot the world-famous boxer for LIFE magazine in 1966 and 1970.

These photographs are the subject of “American Champion,” an exhibition at the Gordon Parks Foundation‘s headquarters in Pleasantville, New York, that opened on June 6—just days after Ali’s death.

Gordon Parks, Trainer Works on Muhammad Ali’s Shoulder, Miami, Florida (1966). Courtesy of and copyright the Gordon Parks Foundation.

Parks first met Ali in 1966, around the time that the boxer made clear that his Muslim faith would not allow him to serve in the Vietnam War. The Foundation credits Parks’s humanizing photographs with helping redefine Ali’s image, when the boxer’s confidence was perceived as arrogance by the press and white American public.

“Every picture he took of Ali captures his essence, grace, and most importantly, his humanity,” foundation executive director Peter W. Kunhardt Jr. told artnet News in a phone conversation. “Not every photographer could capture that moment.”

Gordon Parks, Untitled, London, England (1966). Courtesy of and copyright the Gordon Parks Foundation.

In addition to making a fascinating on-camera subject for Parks and numerous other photographers, Ali was also a gifted artist in his own right. A selection of Ali’s prints that draw heavily on his activism, faith, and athletic career from the estate of Baird Jones will be auctioned at New York’s RoGallery on June 15.

Parks’s photos of Ali benefit from the close relationship between the two men. “These are not just candid quick shots that Gordon was lucky to get,” said Kunhardt. “This was really about friendship.”

Gordon Parks, Untitled, Miami, Florida (1970). Courtesy of and copyright the Gordon Parks Foundation.

“Gordon Parks and Muhammad Ali both were instrumental figures in their fields,” he added, noting that as civil rights activists, “they were in the same fight, so to speak.”

Though Ali’s death has thrust Parks’s images back into the spotlight, there were already plans to mount a major exhibition of them in 2019 at the Nelson-Atkins Museum of Art in Kansas City, Missouri. “They aren’t just pictures that appeared once in LIFE magazine,” Kunhardt said. “They’ll continue to be part of the canon of great 20th century photography.”

See more photos from the exhibition below.

Gordon Parks, Untitled, London, England (1966). Courtesy of and copyright the Gordon Parks Foundation.

Gordon Parks, Muhammad Ali, Miami, Florida (1966). Courtesy of and copyright the Gordon Parks Foundation.

Gordon Parks, Untitled, London, England (1966). Courtesy of and copyright the Gordon Parks Foundation.

Gordon Parks, Untitled, London, England (1966). Courtesy of and copyright the Gordon Parks Foundation.

Gordon Parks, Untitled, London, England (1966). Courtesy of and copyright the Gordon Parks Foundation.

Gordon Parks, Untitled, Miami, Florida (1966). Courtesy of and copyright the Gordon Parks Foundation.

“American Champion” is on view at the Gordon Parks Foundation, 48 Wheeler Avenue, Pleasantville, New York, June 6–September 24, 2016.