As well as its defensive role, the gatehouse served as a barrier to allow for the collection of tolls from those attending markets. Tolls were authorised in the Patent Rolls of 1297 and 1315 and in subsequent town charters.[30] Kissack gives details of the wide variety of items on which tariffs were levied in his reproduction of the charter of 1297. These included "five fat hogs, (a) horse-load of honey and a thousand (roofing) nails".[31] In 1447 Henry VI granted the town a Charter of Incorporation which enabled further development.[32]