CONSERVATOR of the Peace, in the ancient English customs, was a person who had an especial charge, by virtue of his office, to see the king's peace kept. Till the erection of justices of the peace by King Edward III. there were several persons who by common law were interested in keeping the same: some having that charge as incident to other offices; and others simply, or of itself, called custodes, or conservators of the peace. The chamberlain of Chester is still a conservator.
Conservator servant in that county; and petty constables are, by the common law, conservators, &c. in the full sense, within their own jurisdiction: so are also the coroner and the sheriff within their own country. The king is the principal conservator of the peace within all his dominions: the lord chancellor, lord treasurer, lord high steward, lord marshal, lord high constable, all the justices of the court of king's bench, by their office, and the master of the rolls, by prescription, are general conservators of the peace through the whole kingdom, and may commit breakers of the peace, and bind them in recognisances to keep it.
Conservator of the Truce, and Safe Conducts, was an officer appointed in every sea-port, under the king's letters patent. His charge was to inquire of all offences committed against the king's truce, and safe conducts upon the main sea, out of the franchises of the cinque-ports, as the admirals were wont to do, and such other things as are declared anno 3 Hen. V. cap. 6.