To give one law. A sporting term, meaning the chance of saving oneself. Thus a hare or a stag is allowed “law” —i.e. a certain start before any bound is permitted to attack it; and a tradesman allowed law is one to whom time is given to “find his legs.”
Quips of the law, called “devices of Cépola,” from Bartholemew Cépola, whose law-quirks, teaching how to elude the most express law, and to perpetuate lawsuits ad infinitum, have been frequently reprinted —once in octavo, in black letter, by John Petit, in 1503.
The Man of Lawes Tale, by Chaucer. This story is found in Gower, who probably took it from the French chronicle of Nicholas Trivet. A similar story forms the plot of Emare, a romance printed in Ritson's collection. The treason of the knight who murders Hermengilde resembles an incident in the French Roman de la Violette, the English metrical romance of Le bone Florence of Rome (in Ritson), and a tale in the Gesta Romanorum, c. 69 (Madden's edition). (See Constance.)
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894