Harry S. Truman’s middle initial doesn’t stand for anything.

Vintage Truman stamp

Serving as the 33rd President of the United States, Harry S. Truman guided the country out of World War II after the death of his predecessor, Franklin D. Roosevelt, and prepared America for the geopolitical battle ahead: the Cold War. Today, Truman is regarded as one of the nation’s best Presidents, and yet most people probably can’t tell you what his middle initial stands for — because it doesn’t stand for anything. When the future President was born on May 8, 1884, in Lamar, Missouri, his parents couldn’t decide which of Truman’s grandfathers, Anderson Shipp Truman and Solomon Young, to honor with their son’s middle name. Instead, they chose a simple “S” — without a period — for Truman’s middle initial. This atypical name caused some confusion during Truman’s presidential inauguration in 1945, when Chief Justice Harlan F. Stone assigned a middle name to Truman while swearing him into office. He asked the future President to say, “I, Harry Shipp Truman,” but Truman repeated the words with one alteration: “I, Harry S Truman.” Despite the President’s insistence, the name is now officially styled with a period following the middle initial.

Strangely, Truman isn’t the only U.S. President with an unconventional “S” middle initial. Ulysses S. Grant — whose birth name was Hiram, though he went by his middle name, Ulysses — also has an “S” middle initial that stands for nothing. Unlike Truman’s ambiguous tribute to his ancestors, Grant’s “S” was a simple clerical error. In 1839, Congressman Thomas Hamer nominated Grant to the U.S. Military Academy at West Point. Believing Ulysses to be Grant’s first name and at a loss for his middle initial, Hamer wrote in “S” as a stand-in for the cadet’s mother’s maiden name, Simpson. When Grant arrived at West Point, he tried to get the error fixed, but to no avail, and the “S” eventually even appeared on his diploma. The error proved prophetic — after all, U.S. Grant is a pretty good name for any future President.

By the Numbers

Did you know?

Mark Twain helped Ulysses S. Grant publish his memoir.

In 1884, while nearing the end of his life, former President U.S. Grant was hard at work on his memoirs in the hope of leaving something behind for his family, as a failed business venture had left them in financial ruin. A publishing house offered 10% royalties on the book, but famed writer Samuel Clemens — known by his pen name, Mark Twain — arrived at Grant’s home on 66th Street in New York City to make a better offer. Instead of 10% of the sales, Twain promised 70% of the total profit to Grant and his family if he used a publisher owned by the nephew of Twain’s wife. Grant died only a few days after he finished writing in the summer of 1885, and his memoir became an instant bestseller. In early 1886, former First Lady Julia Dent Grant received a check for $200,000 based on the book’s success — at the time, it was the largest royalty check ever written.