Leonardo da Vinci

Leonardo da Vinci was an Italian Renaissance polymath known for his painting and inventions. The diary of the renegade Time Lord known as the Monk recorded a meeting with Leonardo in which he claimed to have provided the inspiration for at least some of da Vinci's inventions which would later seem so advanced for their time. The main one of which was the fact that the Monk gave Leonardo the blueprints for flight. (DW: The Time Meddler)

Circa 1492. Leonardo and his then patron the Duke of Milan were among the guests invited to the masque organized by the young Duke Giuliano of San Martino. Being caught up in the Mandragora Helix's attempt to conquer 15th century Earth, the Doctor missed this opportunity to meet Leonardo, later noting it was probably for the best (DW: The Masque of Mandragora).

Circa 1505, da Vinci was hired by a new patron he knew as "Captain Tancredi", in reality, Scaroth of the Jagaroth. Tancredi asked him to paint six extra copies of his most famous work, the Mona Lisa.

In 1505 the Doctor arrived from 1979 Paris to seek clues to the plot of Count Scarlioni (another of Scaroth's time-splintered selves) to steal the Mona Lisa from the Louvre. After being briefly captured and interrogated by Tancredi wrote "This is a fake" on Leonardo's canvasses in felt tip before returning to the future to try to stop Count Scarlioni. (DW: City of Death)

Although the Doctor did not meet Leonardo in person in that period, he did leave him a note which suggested a degree of familiarity already existed, and that perhaps the two had previously met, or would meet in the future.

Behind the scenes
The title of the episode The Shakespeare Code is a play on the title of the popular Dan Brown novel The Da Vinci Code which dealt with a centuries-old conspiracy theory involving secret codes allegedly included in some of Da Vinci's works. No mention as whether a felt-tip message behind the Mona Lisa reading "This is a fake" was among them.

Da Vinci is one of a very few characters to be referenced in both the Doctor Who and Star Trek franchises, with a holographic recreation of Da Vinci appearing several times in Star Trek: Voyager.