1. Lewis first met Clark after being court-martialed by the Army.

Lewis (L) and Clark (R). (Credit: Jean-Erick PASQUIER/Getty Images)

While serving as a frontier army officer in 1795, a young Meriwether Lewis was court-martialed for allegedly challenging a lieutenant to a duel during a drunken dispute. The 21-year-old was found not guilty of the charges, but his superiors decided to transfer him to a different rifle company to avoid any future incidents. His new commander turned out to be William Clark—the man who would later join him on his journey to the West.

2. Lewis had served as Thomas Jefferson’s secretary.

In 1801, Lewis left the army and accepted an invitation to serve as Thomas Jefferson’s presidential secretary. Lewis had known Jefferson since he was a boy—he’d grown up on a Virginia plantation only a few miles from Monticello—and the pair went on to forge a mentor-protégé relationship while working together in the White House. When Jefferson conceived of his grand expedition to the West in 1802, he immediately named the rugged, intellectually gifted Lewis as its commander. To help the young secretary prepare, Jefferson gave him a crash course in the natural sciences and sent him to Philadelphia to study medicine, botany and celestial navigation.

3. Thomas Jefferson believed the expedition might encounter wooly mammoths.

Woolly Mammoth. (Credit: Royal BC Museum, Victoria, British Columbia)

Before Lewis and Clark completed their expedition, Americans could only speculate on what lurked in the uncharted territories beyond the Rocky Mountains. Even Thomas Jefferson, who’d amassed a small library of books on the frontier, was convinced the explorers might have run-ins with mountains of salt, a race of Welsh-speaking Indians and even herds of wooly mammoths and giant ground sloths. The expedition failed to sight any of the long-extinct creatures, but Lewis did describe 178 previously unknown species of plants and 122 new animals including coyotes, mountain beavers and grizzly bears.

4. The Spanish sent soldiers to arrest the expedition.

Jefferson often described Lewis and Clark’s expedition as a scientific mission to study the lands acquired in the 1803 Louisiana Purchase, but the explorers’ central goal was to find a water route to the Pacific, which would increase trade opportunities and help solidify an American claim on the far Northwest. That was distressing news for the Spanish, who feared the expedition might lead to the seizure of their gold-rich territories in the Southwest. On the suggestions of U.S. Army General James Wilkinson—a Spanish spy—the governor of New Mexico dispatched four different groups of Spanish soldiers and Comanche Indians to intercept the explorers and bring them back in chains. Luckily for Lewis and Clark, the hostile search parties failed to locate them in the vastness of the frontier.

5. Clark brought his slave on the journey.

York statue by Ed Hamilton. (Credit: Dennis Macdonald/Getty Images)

Along with more than two-dozen enlisted men and officers, the Corps of Discovery also included Clark’s personal slave, York. The tall manservant was a hit with frontier tribes, many of whom had never seen a person with dark skin. The Arikara people of North Dakota even referred to York as “Big Medicine” and speculated that he had spiritual powers. Though not an official member of the Corps of Discovery, York made the entire journey from St. Louis to the Pacific and back, and became a valued member of the expedition for his skills as a hunter. When the explorers later voted on where to place their winter camp in 1805, he and the Shoshone interpreter Sacagawea were both allowed to participate. As historian Stephen E. Ambrose later noted, this simple show of hands may have marked the first time in American history a black man and a woman were given the vote.

6. Lewis and Clark’s arsenal included 200 pounds of gunpowder and an experimental air rifle.

The Corps of Discovery carried one of the largest arsenals ever taken west of the Mississippi. It included an assortment of pikes, tomahawks and knives as well as several rifles and muskets, 200 pounds of gunpowder and over 400 pounds of lead for bullets. Lewis also had a state-of-the-art pneumatic rifle he used to impress Indian tribes on the frontier. After pumping compressed air into the gun’s stock, he could fire some 20 shots—each of them almost completely silent. Despite being armed to the teeth, most of the explorers never had to use their weapons in combat. The lone exception came during the return journey, when Lewis and three of his soldiers engaged in a gun battle with Blackfeet Indians that left two natives dead.

7. Sacagawea reunited with her long lost brother during the journey.

“Lewis & Clark at Three Forks,” mural in lobby of Montana House of Representatives. (Credit: Edgar Samuel Paxson)

One of the most legendary members of the Lewis and Clark expedition was Sacagawea, a teenaged Shoshone Indian who had been kidnapped from her tribe as an adolescent. Sacagawea, her husband and her newborn son first joined up with the explorers as they wintered at a Hidatsa-Mandan settlement in 1804, and she later served as an interpreter and occasional guide on their journey to the Pacific. During a run-in with a band of Shoshone in the summer of 1805, she famously discovered the tribe’s chief was none other than her long lost brother, whom she had not seen since her abduction five years earlier. The tearful reunion helped facilitate peaceful relations between the explorers and the Shoshone, allowing Lewis to procure much-needed horses for his trek over the Rockies.

8. Only one member of the expedition died during the trip.

The Lewis and Clark expedition suffered its first fatality in August 1804, when Sergeant Charles Floyd died near modern day Sioux City, Iowa. Lewis diagnosed him as having “bilious colic,” but historians now believe he suffered from a burst appendix. Over the next two years, the expedition endured everything from dysentery and snakebites to dislocated shoulders and even venereal disease, but amazingly, no one else perished before the explorers returned to St. Louis in September 1806. One of the worst injuries came during the trip home, when an enlisted man accidentally shot Lewis in the buttocks after mistaking him for an elk. Though not seriously wounded, the explorer was forced to spend a few miserable weeks lying on his belly in a canoe while the expedition floated down the Missouri River.

9. Lewis later died under mysterious circumstances.

Meriwether Lewis. (Credit: Universal History Archive/Getty Images)

Lewis battled depression and mood swings for most of his life, and his condition only worsened after he returned from the transcontinental expedition in 1806. The great explorer reportedly suffered from money troubles, drinking too much and struggling as the governor of Louisiana. He was twice prevented from committing suicide during an 1809 journey to Washington, but only a few days later, he was found dead in a cabin along the Natchez Trace with gunshot wounds to the head and chest. Some have since speculated he was murdered, but most historians believe he took his own life.

10. Clark adopted Sacagawea’s children.

During her time with the Corps of Discovery, Sacagawea was accompanied by her newborn son, Jean Baptiste, whom the explorers nicknamed “Pomp.” William Clark took a shine to the boy, and when Sacagawea left the expedition in August 1806, he offered to adopt him and “raise him as my own child.” Sacagawea initially turned down the offer, but she later allowed Clark to provide for her son’s education in St. Louis. Following Sacagawea’s death in 1812, Clark became the legal guardian of both Jean Baptiste and her other child, a daughter named Lisette. Little is known about what became of Lisette, but Jean-Baptiste later traveled to Europe before returning to the American frontier to work as a trapper and wilderness guide.