E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
In France, from 768 to 987, the land was encumbered with fortified castles; in England this was not the case till the reign of Stephen. The lords of these castles used to carry off females and commit rapine, so that a class of men sprang up, at least in the pages of romance, who roamed about in full armour to protect the defenceless and aid the oppressed.
Proxima quæque metit gladio is the perfect account of a knight errant.Dryden: Dedication of the Æneis.