Rochester castle was one of the first to be built of stone and at 125 feet is the tallest keep in England.
It was constructed by the Bishop of Rochester in around 1090 in the angle of the Roman town wall. The four-squared towers were added by Archbishop William de Corbell in 1127. The site was jealously guarded by the see of Canterbury until the end of the 12th century.
In 1215 Archbishop Langton failed to follow King John's order to hand over the castle to the Bishop of Winchester, a close supporter of the King. The result was one of the best recorded sieges of the Middle Ages. King John personally besieged the castle for two months but his great stone throwing machines had little affect. He was forced to resort to undermining the walls using pig fat as fuel. Although a whole section of the wall collapsed the inhabitants retreated behind a great cross-wall and refused to surrender until forced by starvation.
The castle was restored but damaged again in a siege of 1264. It was repaired by Edward III and improved by Richard II.
However since that time it was allowed to decay.
In the 18th century plans to demolish the castle were not carried out and thus it remains to the present day.