The Silver Knight was a Cedric the Bull minifigure of the Knights' Kingdom line. The four last sets all included a chrome piece of weaponry or armour to equip him. The two of the four pieces of armour are a Bull Shield and a Cedric helmet, identifying that they are indeed for the Cedric minifigure in the series.
The Chrome Weapons/Armour[]
Cedric with the Silver Helmet
The Silver Breastplate
The Silver Sword
Cedric with the complete set