Happy birthday, Uncle Sam! 

The fatherly yet determined red, white and blue personification of the United States became a symbol of the nation on this day in history, Sept. 7, 1813, according to History.com and other sources. 

"Uncle Sam was inspired by Troy, New York, meatpacker ‘Uncle’ Sam Wilson, who supplied troops with rations way back during the War of 1812," Uncle Sam Rounseville, a Boston-area realtor and philanthropist, told Fox News Digital. 

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Leroy Lincoln Rounseville has some knowledge of this. He legally changed his name to Uncle Sam in 1991 while helping to raise funds for Gulf War veterans. 

He's become a repository of Uncle Sam history and lore and is a familiar figure in full Uncle Sam red, white and blue regalia at ballgames and patriotic events in Boston and around the country. 

"Though the origins of the name Uncle Sam are subject to some dispute, most historians believe that the name came from a New York merchant named Sam Wilson, known by his friends as 'Uncle Sam,'" concurs National Geographic.

Wilson's barrels of beef, according to NatGeo, "were stamped with the initials U.S., for United States, but many associated the initials with ‘Uncle Sam’ Wilson. Over time, Uncle Sam became a synonym for United States."

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Local newspapers soon popularized the story of Uncle Sam, reports History.com.

The New York State Museum offers a detailed account of the origin story. 

Wilson "supplied the Army depot at Watervliet Arsenal New York with rations. Wilson’s wooden barrels were stamped U.S., in broad capital letters, indicating that the food was the property of the United States and intended for American soldiers serving on the northern border with Canada," according to the museum's website. 

"Teamsters, carrying the rations to the troops along rutted tracks, identified the supplies as a gift from their Uncle Sam … It seemed everything came special delivery from Uncle Sam."

The abbreviation "U.S." was a "novelty" in the early days of the nation, reports the Albany Institute, so "receivers of the casks did not know that U.S. meant United States."

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Uncle Sam gained widespread visibility after the Civil War when he was drawn by cartoonist Thomas Nast for major-media outlets. 

Nast is the same artist who popularized early images of red-clad jolly old elf Santa Claus in late 19th-century America. 

But the image of America took on his more recognizable likeness in a series of U.S. Army recruiting posters by artist James Montgomery Flagg during World War I. 

Flagg's Uncle Sam was a gray-haired man with steely eyes, gray hair and beard, wearing a star-spangled American flag top hat. He's often shown in rolled-up shirtsleeves in a feisty pose with muscular forearms. 

Flagg's Uncle Sam was renewed in World War II recruiting posters and remains a familiar image of the United States around the world today. 

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Wilson, the inspiration for Uncle Sam, was born in Arlington, Mass., in 1766. He moved to Mason, N.H., as a boy and, at age 14, joined the Continental Army, according to a 1936 biography in the Troy Times-Record. 

He moved to upstate New York around 1788. 

Wilson is honored today with memorials in both Arlington, Mass., and Troy, N.Y.

"Wilson died at age 87 in 1854, and was buried next to his wife Betsey Mann in the Oakwood Cemetery in Troy, New York, the town that calls itself 'The Home of Uncle Sam,'" writes History.com.