Former President Franklin D. Roosevelt used a wheelchair in private, a secret he and his staff kept hidden until his death.

An Indiana college professor has now uncovered rare footage that appears to show Roosevelt moving in a wheelchair during a visit to the U.S.S. Baltimore, then stationed at Pearl Harbor, in July 1944. Ray Begovich, a journalism professor at Franklin College, said he found the footage by chance in the National Archives while researching an unrelated subject.

In the eleven-second clip, Roosevelt can be seen exiting a doorway and moving along a row of sailors. He's mostly obscured by the men and a banner along a railing in the foreground, but he appears to be seated while moving smoothly along.

A spokesperson for the National Archives told the Associated Press that while it could not "definitively" confirm the footage as the earliest existing film of Roosevelt in a wheelchair, she said that "such footage is certainly rare."

Roosevelt was stricken with polio in 1921, which cost him much of the use of his legs. But the four-term president went out of his way to hide his disability from the public, fearing a backlash from voters.