Sir Knight John Radcliffe (c.1269 – 1357) was the 25th great-grandfather of Cometan, classified as one of Cometan’s medieval paternal ancestors in the Taylor family line.

Born in Wordsall, Lancashire, Sir John was the husband of Joan de Holland and is also known to have been the father of Sir Richard Radcliffe of Ordsall (1320 – 1380). Sir John was also the son of Richard Radcliffe and Isabella de Radcliffe. Sir John is also believed to have died in Wordsall, Lancashire.

In Cometanic ancestry, Sir John is categorised as part of the 27th generation retrograde, and because he was born before 1453, he is classified as a medieval ancestor of Cometan, a title that is rarely bestowed.