In 1573 Bishop's Castle was made a borough by a charter granted by Elizabeth I. This film shows the celebrations of the 400th anniversary of the charter in 1973.
This charter, and a later on granted by James I, were kept in a locked box at a local bank. For many years, as BBC News reported in 2011, they could not be consulted as the key to the box had been lost:
Town Clerk Diane Malley said: "In the 1970s we did have access to the charters because for a short time they were on display in the town hall, and sometime after that they were locked in the bank and the keys mislaid."
Mrs Malley found an envelope marked "unknown keys" in a cupboard and decided to see if one of them would unlock the charter box.