The Time Lords are a fictional humanoid species originating on the planet Gallifrey, seen in the British science fiction television series Doctor Who. They are called "Time Lords" because of their ability to travel in and manipulate time through prolonged exposure to the time vortex.

Rassilon is a fictional character in the British science fiction television series Doctor Who. In the backstory of the programme, he was the founder of Time Lord society on the planet Gallifrey and its first leader, as Lord High President. After the original television series ended in 1989, Rassilon's character and history were developed in books and other media.