1. The “S” in Grant’s name didn’t stand for anything.

Although he was always known as “Ulysses” during his youth in Ohio, Grant’s given name was actually Hiram Ulysses Grant. His phantom middle initial is the result of an error from Ohio Congressman Thomas Hamer, who accidentally wrote the future general’s name as “Ulysses S. Grant” when he nominated him to attend West Point. Despite Grant’s best efforts to correct the record, the name stuck, and he eventually accepted it as his own. “Find some name beginning with “S” for me,” he joked in an 1844 letter to his future wife, Julia Dent. “You know I have an “S” in my name and don’t know what it stands for.”

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2. He was notoriously unlucky in business.

After spending a decade in the army and serving with distinction in the Mexican-American War, Grant resigned his post in 1854 and spent the next seven years flopping as a farmer, real estate agent and rent collector. He once had to eke out a living by selling firewood on St. Louis street corners, and when the Civil War erupted, he was toiling away in obscurity at his family’s Galena, Illinois leather business. Grant would later try his hand at business a second time after he left the White House, with equally disastrous results. A financial firm he started with his son and a man named Ferdinand Ward went belly up after Ward fleeced its investors, and by 1884, Grant was bankrupt. It was only after the posthumous publication of his memoirs that his fortune was restored.

3. Grant won the first major Union victory of the Civil War.

Grant struggled to secure a field command at the outbreak of the Civil War, but was later placed in charge of a regiment of Illinois volunteers and quickly promoted to the rank of brigadier general. The first display of his trademark aggressive style came in February 1862, when he forced the capitulation of some 15,000 Confederates at Tennessee’s Fort Donelson. “No terms except complete and unconditional surrender can be accepted,” he famously warned the garrison’s commander. The victory marked the first time in the war that a full Confederate force was captured, and grateful Northerners inundated “Unconditional Surrender” Grant with cigars after it was reported that he smoked one during the attack. Before the war ended, Grant would accept the surrender of two more rebel armies at Vicksburg, Mississippi and Appomattox Court House, Virginia.

EXPLORE: Ulysses S. Grant: An Interactive Map of His Key Civil War Battles

4. He struggled with alcohol throughout his life.

Grant’s taste for strong drink first became problematic in the early 1850s, when he was reportedly forced to resign from the army for being caught drunk on duty. He swore off alcohol for most of the next decade, only to fall off the wagon during the Civil War. Grant’s penchant for binge drinking was usually kept in check by his teetotaler adjutant, Colonel John Rawlins, but rumors that he was intoxicated during battles swirled around him for most of the war. For his part, Abraham Lincoln appeared unperturbed by the gossip. When a group of congressmen once alleged that Grant was a drunk, the President supposedly responded by asking what kind of whiskey the General preferred. “I urged them to ascertain and let me know,” Lincoln later said, “for if it made fighting generals like Grant, I should like to get some of it for distribution.”

5. Grant hated wearing army uniforms.

Grant received numerous demerits for his unkempt uniforms during his days at West Point, and his distaste for military dress continued even after he assumed supreme command of the Union Army during the Civil War. Unlike many of his epaulet-wearing contemporaries, he rarely carried a sword and often took to the field clad in a civilian hat, mud-caked boots and an ordinary private’s coat with his rank stitched onto it. One observer who saw Grant during the war described him as an “ordinary, scrubby-looking man, with a slightly seedy look, as if he was out of office on half-pay.”

6. He was supposed to be at the theater with Lincoln on the night of his assassination.

Grant was invited to join Abraham Lincoln at Ford’s Theatre on the fateful evening of April 14, 1865, but was forced to decline after he and his wife made plans to visit their children in New Jersey. He was informed of the President’s assassination when his train stopped later that night. Grant later described Lincoln’s death as the “darkest day of my life,” and bitterly regretted not having been at his side. Despite being a potential target himself, he was convinced he would have somehow stopped John Wilkes Booth from pulling the trigger.

READ MORE: 10 Things You May Not Know About the Lincoln Assassination

7. Grant prevented Robert E. Lee from being charged with treason after the Civil War.

When he accepted the surrender of Robert E. Lee’s Army of Northern Virginia in April 1865, Grant offered generous terms that paroled Confederate soldiers and officers and allowed them to return to their homes. He even permitted the men to keep their horses and mules for use as farm animals. Grant believed leniency was critical to achieving a lasting peace, and he was furious when a federal grand jury later negated the terms of his agreement and charged Lee and several other Confederate generals with treason. During a subsequent meeting with President Andrew Johnson, he stated his intention to “resign the command of the army rather than execute any order to arrest Lee or any of his commanders so long as they obey the law.” Unwilling to lose Grant’s support, Johnson reluctantly dropped the case.

8. He had no political experience before becoming president.

His time in charge of the Union Army notwithstanding, Grant was a political novice when he was inaugurated as the 18th president in 1869. He’d never held any elected position, and had shown little interest in running for office before the Republican Party nominated him as its candidate. Critics would later blame his lack of experience for the economic turmoil and scandals that dogged his administration, a claim that Grant himself acknowledged. “It was my fortune, or misfortune, to be called to the office of Chief Executive without any previous political training,” he wrote in his final message to Congress. “Under such circumstances, it is but reasonable to suppose that errors of judgment must have occurred.”

9. He was responsible for dismantling the KKK during Reconstruction.

After the newly formed Ku Klux Klan began murdering and terrorizing black Americans in the late-1860s, President Grant mobilized the Justice Department and secured thousands of indictments against their leaders. In 1871, he also oversaw passage of the so-called “Ku Klux Klan Act,” which armed him with the power to declare martial law and suspend habeas corpus in areas deemed to be in a state of insurrection. The law got its first test later that year, when Grant sent troops into South Carolina and ran thousands of Klansmen out of the state. Thanks to his administration’s efforts, the hooded extremists were effectively cowed into submission over the next few years. They wouldn’t resurface in force until the 1910s.

10. Mark Twain published his memoirs.

Grant first began compiling his memoirs in the mid-1880s, after he wrote a series of popular articles about his Civil War experiences. He was on the verge of signing a book deal with a magazine when novelist Mark Twain swooped in and offered a much more lucrative contract with his newly formed publishing firm Charles L. Webster & Company. Grant took Twain up on his offer, and later finished the book just a few days before succumbing to cancer in July 1885. The Personal Memoirs of U.S. Grant hit stores later the year, and was immediately hailed by Twain and others as a literary masterpiece. It was also a massive bestseller. After the book was published, Grant’s widow Julia received a whopping $450,000 in royalties.