 The 19th century saw efforts to preserve the castle . In 1826 repairs were made to the well in the keep . At the same time a survey was carried out by A. W. N. Pugin and he excavated around the keep , investigating how it was built . He descended into the well in a bucket in an unsuccessful search for treasure . Victor Child Villiers , 7th Earl of Jersey , leased the castle to the Corporation of Rochester in 1870 for use as a public park ; when it opened to the public in 1872 , Rochester Castle was presented as a picturesque ruin , with trees planted in the enclosure and the walls overgrown with ivy . In 1884 the Corporation bought the castle for £ 6 @,@ 572 ( equivalent to £ 3 @.@ 4 million in 2009 terms ) . Between 1896 and 1904 , George Payne carried out repairs . In the first quarter of the century the gardens acquired a German field gun and a tank from the First World War , and a bandstand , though they were removed by 1961 . Ivy was removed from the keep between 1919 and 1931 and the planting in the castles scaled back . In 1960 the origin of Boley Hill was investigated archaeologically , but the excavations failed to provide firm dating evidence . 
