The name Tristan has its origins in the Celtic language of Brittonic, which was spoken in parts of present-day Britain during the medieval period. It is derived from the elements "tryst" meaning "sad" or "sorrowful" and the suffix "-an" indicating a diminutive form. The original Brittonic form was likely "Drystan" or "Trystan."

One of the earliest known references to the name Tristan comes from the medieval legend of Tristan and Iseult, which dates back to the 12th century. This tragic romance, originating in the legends of the Cornish region of Britain, tells the story of the Cornish knight Tristan and his ill-fated love for the Irish princess Iseult.

The earliest recorded person with the name Tristan was Tristan de Mareuil, a French knight who lived in the 12th century. Other notable historical figures bearing the name include Tristan l'Hermite (1601-1655), a French poet and playwright, and Tristan da Cunha (1506-1548), a Portuguese explorer and navigator who lent his name to the remote Tristan da Cunha archipelago in the South Atlantic Ocean.

In the realm of literature, one of the most famous Tristans is the protagonist of the 12th-century epic poem "Tristan and Iseult" by the Norman poet Béroul. This work, along with other versions of the legend by authors like Gottfried von Strassburg and Thomas of Britain, helped to popularize the name across Europe.

Another notable Tristan was Tristan de Salazar (c. 1510-1573), a Spanish conquistador and explorer who participated in the conquest of Guatemala and served as governor of Yucatán. In the realm of music, the name was borne by Tristan Murail (born 1947), a French composer and one of the founders of the spectral music movement.

Despite its Celtic origins, the name Tristan has been used across various cultures and regions throughout history, with its popularity ebbing and flowing over time. Its association with the enduring medieval legend has contributed to its enduring appeal and recognition across generations.