One hypothesis as to its origin is based upon The History of the Rebellion and Civil Wars in England, by Edward Hyde, 1st Earl of Clarendon.
[1] A book entitled Lives of the Most Remarkable Criminals (1735) states that Charles II passed an act "whereby any person with malice aforethought by lying in wait unlawfully cutting out or disabling the tongue, putting out an eye, slitting the nose or cutting off the nose or lip of any subject of His Majesty ... shall suffer death."
[2] An early example of the idiom is from the Club book of the Tarporley Hunt (1765):[3] Mr. John Barry having sent the Fox Hounds to a different place to what was ordered was sent to Coventry, but return'd upon giving six bottles of Claret to the Hunt.By 1811, the meaning of the term was defined in Grose's The Dictionary of the Vulgar Tongue: To send one to Coventry; a punishment inflicted by officers of the army on such of their brethren as are testy, or have been guilty of improper behaviour, not worthy the cognizance of a court martial.
The person sent to Coventry is considered as absent; no one must speak to or answer any question he asks, except relative to duty, under penalty of being also sent to the same place.
[4]According to William Clark in Tales of the Wars (1836), the phrase originates from a story about a regiment that was stationed in the city of Coventry but was ill-received and denied services.