appointed by letters patent.
The following are sometimes included, though not appointed by letters patent:—Chaucer, Gower, John Key, Bernard, Skelton, Rob. Whittington, Richard Edwards, Spenser, and Sam. Daniel.
(!) Five of the fourteen known only by their names. Three others quite third-rate poets. The remaining five were distinguished men.
A poet laureate is one who has received a laurel crown. There were at one time “doctors laureate,” “bachelors laureate,” etc.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894