Complete the indicated task to unlock the corresponding medal.

Medal of Lancelot: Defeat Lancelot and collect the game piece after the level. This medal changes the music to "All Hail Shadow" by Crush 40.
Medal of Gawain: Defeat Gawain and collect the game piece after the level. This medal changes the music to Knuckles' theme from Sonic Adventure.
Medal of Percival: Defeat Percival and get the game piece after the level. This medal changes the music to that which plays when you fight Blaze in Sonic Rush.
Medal of Sonic: Complete the "Knights Passage" legacy stage and get the game piece after the level. This medal changes the music to "What I'm Made of" from Sonic Heroes.