In the medieval legend of Tristan and Iseult this was the name of a king of Cornwall. It was also borne by the American author Mark Twain (1835-1910), real name Samuel Clemens, the author of The Adventures of Tom Sawyer and Adventures of Huckleberry Finn. He took his pen name from a call used by riverboat workers on the Mississippi River to indicate a depth of two fathoms. This is also the usual English spelling of the name of the 1st-century BC Roman triumvir Marcus Antonius (Mark Antony).
This name was borne by two 20th-century kings of Belgium. Other famous bearers include the German physicist Albert Einstein (1879-1955), creator of the theory of relativity, and Albert Camus (1913-1960), a French-Algerian writer and philosopher.