What is "licence to crenellate"

n. In medieval Britain, a licence, granted by the king giving permission to fortify a manor house.

In medieval England, Wales and the Channel Islands a licence to crenellate (or licence to fortify) granted the holder permission to fortify their property. Such licences were granted by the king, and by the rulers of the counties palatine within their jurisdictions, i.e. by the Bishops of Durham, the Earls of Chester, and after 1351 by the Dukes of Lancaster.

Licences to crenellate were issued in the 12th to 16th centuries. The earliest licences present a point of contention, for instance though authorities such as John Goodall in his book The English Castle considers a charter of 1127 to be one such licence, it was rejected as such by Philip Davis. In 1199 the administration of the country began to be systematically recorded, and the majority of licences survive in the Patent Rolls. Letters patent were distributed and were a public declaration that the person named within had been granted permission by the king to build a fortification. During periods of conflict, the number of licences granted usually increased. Only in a small number of cases did the Crown levy fees against those applying for licences to crenellate, and then was only a small amount, a mark or half a mark.

While licences were mostly granted to men, eleven women are mentioned in the surviving licences and four licences were granted directly to women. Of those given permission to build fortifications, most were knights rather than the upper members of the aristocracy. Most applicants were individuals; however, towns could also apply and 28 licences relate to town defences. And while most people who secured licences were secular, ecclesiastic institutions were also eligible so 44 relate to churches, abbeys, and cathedrals.