Leonardo da Vinci

Leonardo da Vinci was an Italian Renaissance polymath known for his painting and inventions.

Biography
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 Leonardo's inventions which would later seem so advanced for their time. The main one of these was the Monk's claim that he gave Leonardo the blueprints for flight. (DW: The Time Meddler)

Leonardo invented a primitive flight machine. It was used by Astrolabus while he was fleeing from the Sixth Doctor. (DWM: Voyager)

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

Circa 1505, Leonardo 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. (DW: City of Death) One of these copies was painted using oil pigments he borrowed from a neighbouring artist, Giuseppe di Cattivo. Unbeknowst to both of them, the minerals used in this paint would bring the painting to life in future. (SJA: Mona Lisa's Revenge, SJAF: Sarah Jane's Alien Files episode 5)

In 1505 the Fourth 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, the Doctor wrote "This is a fake" in felt pen on the boards Leonardo would paint the extra Mona Lisa copies before returning to the future to try to stop Count Scarlioni. (DW: City of Death)
 * Although the Doctor did not meet Leonardo in person at that time, he did call to him and leave him a note in a manner which suggested a degree of familiarity already existed, implying that the two had previously met.

Among a long strip of business cards for various famous scientists and luminaries owned by the Sixth Doctor was one which read "da Vinci." (DW: The Two Doctors)

Other Timelines
In an alternate universe where all of history happened at once, Da Vinci seemingly wrote The Da Vinci Code. (REF: The Brilliant Book 2012)

Behind the scenes

 * "Da Vinci" was not a family name, and Leonardo was never known to have used a surname in the modern sense. This part of his name merely means "of Vinci," indicating that Leonardo was born in Vinci, a town near Florence. It is therefore grammatically incorrect to refer to Leonardo as simply "da Vinci," though that form of address remains in somewhat common use and has appeared in The Two Doctors, the TV movie and The Hungry Earth as well as the title of Da Vinci's Robots.
 * 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 Leonardo's works. (No mention as whether a felt-tip message behind the Mona Lisa reading, "This is a fake" was among them.) The Da Vinci Code was itself heavily inspired by the non-fiction book The Holy Blood and the Holy Grail by former Doctor Who scriptwriter Henry Lincoln.
 * Leonardo da Vinci is one of very few characters to be referenced in both the Doctor Who and Star Trek franchises, with an immortal human claiming to have been him appearing once in Star Trek: The Original Series ("Requiem for Methuselah"), and a holographic recreation of him appearing twice in Star Trek: Voyager ("Scorpion" and "Concerning Flight").