How Sam Clemens Became Mark Twain

Mark Twain

Within a week of first using the pseudonym, Clemens received a fan letter addressed to “Mark Twain” – from then on, he was “Sam” only to his family and close friends.

Samuel Langhorne Clemens (1835–1910) was without doubt the best known American author of his time. Around the world, he may well have been the best known American of his time. But he was known, not as Sam Clemens, but as Mark Twain, a pseudonym he chose and first used in 1863, early in his career as a writer and humorist. His reasons for selecting that name are not as straightforward as they might seem.

Why Use a Pen Name at All?

Clemens used other pseudonyms before settling on Mark Twain – everything from the unadorned “Josh” to the highly adorned “Thomas Jefferson Snodgrass.” Pen names were customary at the time; they helped create an author’s identity, and they could readily be changed if the author wished to move in a different literary direction. For Clemens, there was an additional value in a pseudonym: he could hide behind it if his writing gave offense – and given Sam’s sharp wit, this was a distinct possibility.

The Meaning of “Mark Twain”

Before becoming a writer, Clemens had had a brief career as a Mississippi River steamboat pilot. On the river, the depth of water was measured by casting out a rope with a lead weight attached to its end, and knots positioned one fathom (six feet) apart along its length. The leadsman would call out the depth as the boat made its way from the dock into the main channel: “By the mark, one!” meant a depth of one fathom. When the depth reached two fathoms, there was sufficient water to allow the boat to increase its speed safely, and the cry was “By the mark, twain!” Thus “Mark Twain” conjured up the reassuring call that meant safe water.

Why Clemens Chose “Mark Twain”

Later in life, Clemens said that “Mark Twain” was first used as a pen name by a Captain Isaiah Sellers in his dispatches about river conditions to the New Orleans newspapers. When Sellers died, Clemens adopted the use of his pseudonym for himself. This explanation, however, seems to be one of Clemens’s many literary inventions. The New Orleans papers of the time reveal no use of “Mark Twain” as a pseudonym, and Sellers didn’t die until a year or more after Clemens had begun to use the name. Why did Clemens make up a story about having borrowed “Mark Twain” from someone else? One possibility is that he was trying to discredit a story being circulated at the time that “Mark Twain” referred to Clemens’s ability to do enough drinking for two people.

Whatever the reason he chose it, “Mark Twain” turned out to be just the right fit for the writings of Sam Clemens. It was a solid name, unmistakable, with a bit of a bite – like the man himself. Clemens once wrote that the difference between the right word and the almost right word was the difference between the lightning and the lightning bug. For Sam Clemens, “Mark Twain” was exactly the right name.


  1. Lauber, John. The Making of Mark Twain: A Biography. New York: Noonday Press, 1985.