Medieval as in "realistic knights and templars", medieval as in "swords and sorcery", medieval as in "gothic aesthetic reminiscent of 12th-17th century Europe or feudal Japan, but actually taking place whenever they feel like", medieval as in "brutal and/or primitive in design", or the far more restrictive but simplistic "pre-industrial setting"?
because: Ghouls and Ghosts (series), Dragon Age (series), Fable (series), Dynasty Warriors (series), Romance of the Three Kingdoms (series, including Pokemon Conquest), Castlevania (entire series), Bioshock, Enslaved: Oddysey to the West, Deadliest Warrior: the Game... there are more.
Also, games that never were on the PC? or were originally designed for console, but later ported to PC?
because: Final Fantasy (series, except XI and XIV), Dragon Warrior/Quest (series), every turn-based RPG ever for that matter, Kingdom Hearts (series)...
Also, is this limited to video games?
because: Magic: the Gathering, Dungeons and Dragons (and its ilk), The Once and Future King, Settlers of Catan, Wrestling, Jousting, Decathlon (and many other Track and Field sports), Horse Racing (and it's more modern iterations...)