Don Juan was a Spanish nobleman of Earth literature and music. He was a legendary seducer of women.

In the 18th century, Don Juan was the subject of Wolfgang Amadeus Mozart's opera Don Juan. (VOY: "Virtuoso")

In 2267, while strolling on the Shore Leave Planet, Yeoman Tonia Barrows thought the place had a story book atmosphere about it. She daydreamed how she would like to meet a man, a man like Don Juan, in a place like this. The planet's computer, using her knowledge of the character, recreated Don Juan. (TOS: "Shore Leave")

According to the Star Trek Encyclopedia (4th ed., vol. 1, p. 215), Don Juan first appeared in a 16th century play by Tirso de Molina. The play was set in the 14th century.