One of the two provincial heralds, with jurisdiction over the southern provinces. The name was taken in honour of the Duke of Clarence, third son of Edward III. The herald of the northern provinces is called Norroy King-of-Arms.
Garter-King-of-Arms, also “Principal King-of-Arms,” has to attend on Knights of the Garter, and arrange whatever is required in connection with these knights. There is a Bath King-of-Arms, not a member of the college, to attend on Knights of the Bath.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894