"The only thing we have to fear is fear itself."

Those powerful words were uttered by President Franklin Delano Roosevelt in his first inaugural address as he took office as the 32nd president during one of the most challenging times in the nation’s history.

His remarks came in the throes of the Great Depression, when Americans were losing jobs at a record pace, families were unable to afford food and banks were closing in a panic that was spreading across the United States. FDR's words prefaced his actions to stabilize the U.S. economy in its darkest days.

But even as the nation was recovering from the Great Depression, FDR faced another crisis. America had stayed out of World War II until the Japanese attacked Pearl Harbor on December 7, 1941, forcing forced his hand.

America declared war.

Paul Sparrow, director at the Roosevelt Library and Museum in Hyde Park, New York, recalled the powers of persuasion FDR used so effectively, particularly in his fireside chats on the radio just six months after the U.S. entered the war.

Sparrow called it a brilliant piece of political persuasion since "it reassured them, but he was also not pretending it wasn't going to be difficult, he wasn't creating a false sense of hope for them, he was saying here's the situation. He was very specific about it and again, it was one of those things where at the point of great trepidation in this country, he provided encouragement and a sense of accomplishment."

FDR's charisma, leadership and confidence overshadowed a challenge most Americans didn't even know he faced. In 1921, when he was 39, Roosevelt was diagnosed with polio, making him the first president with a significant physical disability.

Many believe coping with that made him a stronger person and president despite the fact that he went to great lengths to hide the disability. But Sparrow said he did so with good reason. "I think prejudice against people with disabilities has decreased significantly since then, when there was almost an assumption if you had a physical disability, you might also have a mental disability."

The only American president ever elected four times was a defining figure in American history. Franklin Delano Roosevelt died just under three months into his fourth term at the age of 63. In those years he saw many successes as well as failures.

But he lived by his own words, "It is common sense to take a method and try it. If it fails, admit it frankly and try another, but above all try something."