This series consists of the Caption of Seisin of the Cornish possessions of the Duchy of Cornwall, taken on behalf of Edward, eldest son of Edward III, in May 1337.
The purpose of the document was for seisin to be taken of the Cornish lands, knights' fees, jurisdictions, assets and privileges with which the duke was endowed.
The caption comprises surveys of the manors, knights' fees and castles of the duchy, and of other Cornish revenues belonging to the duchy, such as the shrievalty of Cornwall and the profits of the Stannary courts. Included are the names, holdings, rents and services of the free tenants; the free conventionaries, that is the free tenants holding under the assession system; the unfree conventionaries who held at will; and those who held in villeinage.
Borough surveys include claims to liberties, copies of charters and, in some instances, lists of burgesses. The last section of the document deals with the farms of the ports, levied by the duke's haveners and assessed according to the number of fishing boats each port supported, and including too the profits of court and rents and fines of stallholders, prises of wine, and wreck of the sea.