Mona Lisa

A colloquial term for La Gioconda, any of seven paintings by Leonardo da Vinci painted in 1505, as seen in the Fourth Doctor story City of Death.

The paintings were commissioned by Scaroth of the Jagaroth as part of a scheme to raise money in 1979 to fund research into time travel, in order to journey back to the scene of the destruction of Scaroth's starship which destroyed his race and left Scaroth splintered in time. While the Doctor did not prevent the "forgeries" of the extra six paintings (if, in fact, they could be considered forgeries, since they were all painted by Da Vinci), he did ensure that future X-ray machines would be able to discover their provenance by writing "THIS IS A FAKE" on the blank canvas of each before Da Vinci painted them.