Flint

"Flint" is an immortal encountered by Kirk and the crew of the Enterprise on stardate 5843.7 on the planet Holberg 917-G while searching for mineral ryetalyn to cure a plague that was infesting the ship. He claimed to have been born on Earth in the year 3834 BC in Mesopotamia. He claimed to have been, among many others, Alexander the Great, Leonardo DaVinci, Johannes Brahms,, King Solomon, Merlin, Methuselah, Abramson, and his collections imply that he was William Shakespeare, Reginald Pollack and Sten from Marcus II. He was also Mr. Brack.

He appears in (TOS episode: Requiem for Methuselah; TNG novel: Federation); TNG novel: Immortal Coil).