Eratosthenes

Eratosthenes was a mathematician. He lived three centuries apart from Aristophanes In an alternate timeline, the First Doctor encountered him and Aristophanes arguing in a library in Egypt in the fourth century BC. In this timeline, Eratosthenes would not be born for another 350 years after 322 BC, but had come to the library via the time-travel portals set up by Rhakotis. (PROSE: The Book of Shadows)

Behind the scenes
In the real world, Eratosthenes was born in 276 BC, which is only 46 years after 322 BC.