The Crowstone’s copper plate – now turned green – records that it was erected in 1836 and marked the seaward limit of the River Thames as then controlled by the City of London, and that it replaced a stone of 1755, both standing together until the more aged of the pair was presented by the Port of London Authority to Southend Corporation in 1950 for preservation in Priory Park
Until 1350, the English Crown held the right to fish the rivers of England and charged duties on those people it licensed to fish. In 1197 King Richard I, in need of money to finance his involvement in the Third Crusade, sold the rights over the lower reaches of the River Thames to the City of London. Marker stones were erected to indicate the limit of the City's rights.