A lifelong slave and personal servant of William Clark, York participated in the entire exploration and made significant contributions to its success.

[17]: 5  For all intents and purposes, York's role in Lewis and Clark's Corps of Discovery was equal to that of the expedition's white men.

The expedition apparently maintained none of the usual restrictions on the movement of enslaved people, and while opportunities to escape may have appeared, York remained with the Corps of Discovery.

[18] The following excerpts are from the expedition's official report: [October 9, 1804] The object which appeared to astonish the Indians most, was captain Clark's servant [slave] York, a remarkable stout strong negro.

By way of amusement he told them that he had once been a wild animal, and caught and tamed by his master, and to convince them, showed them feats of strength, which added to his looks made him more terrible than we wished him to be.

[19]: 102 [October 12, 1804] These women are handsomer than the Sioux; both of them are however, disposed to be amorous, and our men found no difficulty in procuring companions for the night by means of the interpreters.

The black man York participated largely in these favours; for instead of inspiring any prejudice, his colour seemed to procure him additional advantages from the Indians, who desired to preserve among them some memorial of this wonderful stranger.

[19]: 105–106 [8][page needed] (Numerous other reports confirm that women of these tribes, with their husbands' encouragement, would seek to have sexual intercourse with white men.

[19]: 138 [March 9, 1805] In the course of the conversation, the chief observed that some foolish young men of his nation had told him there was a person among us who was quite black, and he wished to know if it could be true.

We assured him that it was true, and sent for York: the Borgne [Indian chief] was very much surprised at his appearance, examined him closely, and spit on his finger and rubbed the skin in order to wash off the paint; nor was it until the negro uncovered his head, and showed his short hair, that the Borgne could be persuaded that he was not a painted white man.

[19]: 168 [August 17, 1805] They had indeed abundant sources of suspiscion in all they saw: the appearance of the men, their arms, their clothing, the canoes, the strange looks of the negro, and the sagacity of our dog, all in turn shared their admiration.

[19]: 384 York is not mentioned by name, but at their 1805–06 winter camp on the Columbia River, Indians brought their women to market "for a fishinghook or a string of beads", resulting in cases of "venereal disease".

[10] York became the first African-American man to reach the Pacific Ocean when he walked nineteen miles (30 km) from camp with Clark.

[22] In a reply, Dayton Duncan notes that Clark wrote down the views on the question of every member of the expedition, including York and Sacagawea.

[5] All the men of the expedition except York received double pay according to rank, $5 to $30 per month, and each enlisted man was granted 320 acres (130 ha) of land.

[4]: 110 Historian Robert Betts said the freedom York had during the Lewis and Clark expedition made resuming enslavement unbearable.

[15]: 2  From them it was discovered that York had a wife, and that his marriage antedated the expedition,[15]: 98  which was deliberately made up primarily of unmarried men, like Lewis and Clark themselves.

By November 1808, Clark was angered by York's refusal to accept the move to St. Louis and repeated requests that he be hired out in Louisville or sold to someone there.

As Clark wrote his brother when finally giving in, he decided to: send York...and promit him to Stay a few weeks with his wife.

An 1811 letter from a Louisville relative reported that "I don't like him nor does any other person in this country",[4]: 164  and also that the owner of York's wife was going to move to Natchez, Mississippi.

According to Darrell Millner, there is nothing to corroborate any of these claims, and York's alleged desire to return to slavery "lacks historical foundation".

[3]: 310  Clark's story is self-serving and reflects pro-slavery arguments that Africans were happy to be slaves and could not lead successful lives as free people.

The Indians guessing his purpose, and inspired by his words and fearless example, followed close to his heels, and were in the fort dealing destruction to the right and left nearly as soon as the old man.

However, as reported in a letter that was only discovered in the late 1930s, Rose was apparently killed by Indians during the winter of 1832–1833, which means he could have not have been the black man Leonard saw in 1834.

[4]: 137 James Beckwourth, who left a lengthy autobiography,[27] was a former slave who became a scout, rancher, and mountain man in the West and lived among the Crow for much of the time between 1829 and 1836.

"[29] A John Brazeau was an employee of the American Fur Company and founded Braseau's Houses, a trading post on the Yellowstone River.

After his wife was taken to Natchez, York no longer had a reason to remain in Louisville, and he was quite upset at Clark's refusal to grant him his freedom, given his "immense services" during the expedition.

His role and contributions are systematically reduced to behavior that was considered fitting and appropriate for a negro, ignoring the positive aspects of York's character and contributions, distorting some incidents to cast them in the most unfavorable light possible, and projecting onto York unsubstantiated qualities, such as a thick "Negro" dialect and an insatiable sexual appetite.

[3]: 306–307 In contrast, the superhero presentation of York has elevated him "to near superhuman status and his contributions to the expedition were unsurpassed by others in the Corps of Discovery.

The superhero York is the quintessential role model, a courageous, ingenious, brave, and self-sacrificing black hero who has overcome all of the obstacles that slavery and a hostile frontier threw at him.