Galileo Galilei was an Italian mathematician, astronomer, and philosopher.
In 1609, Galileo was in Venice to show the Doge his telescope when he encountered the First Doctor, Steven Taylor, and Vicki Pallister, who had come to Venice responding to a mysterious invitation. Since the Doctor required Galileo's assistance at the same time he was scheduled to demonstrate the invention, Steven had to impersonate Galileo by means of a holographic disguise. The Doctor also helped Galileo improve his telescope design. (PROSE: The Empire of Glass)
References
Professor Kettlewell mentioned Galileo while speaking about unappreciated scientists with the Fourth Doctor. (TV: Robot)
The Fourth Doctor thought Galileo would be impressed by in-station fusion satellites, devices used as artificial suns. (TV: The Sun Makers)
Sarah Jane Smith said that she didn't think that Galileo and Copernicus were carrying out experiments in the paranormal. (TV: The Lost Boy)
