Corfe Castle in Dorset was partially ruined by a six-week long siege during the Civil War.
Plans to restore a medieval ruined castle which was a stronghold in the time of William the Conqueror have been announced.
The £700,000 repair work to Corfe Castle, in Wareham, Dorset, will help conserve the 1,000-year-old monument for future generations.
The ruin has stood the test of time to become a popular tourist attraction and it is now a protected archaeological site of national importance, with Scheduled Ancient Monument status.
A two-year conservation programme by the National Trust and English Heritage will re-open the top third of the castle, including the keep and inner ward section, to more than 100,000 visitors each year.
Perched in a gap in the Purbeck ridge, the castle has a turbulent history.
It controlled the gateway through the Purbeck Hills and was thought to have been an important Roman defensive site.
Monarchs have come and gone, including 13th century King John who built a hall, chapel and domestic buildings.
Henry III constructed additional walls and towers, while Queen Elizabeth I sold it to Sir Christopher Hatton, her supposed suitor, in 1572.
By 1643 the Parliamentarians occupied most of Dorset, and the castle then survived a six-week siege, followed by a number of blockades, and a second siege started by Colonel Bingham, Governor of Poole.
The castle was then betrayed from within and the Roundheads took over in February 1646.
The castle left standing today was built in the 11th century, rebuilt from a wood castle in the ninth century.
Corfe was also the inspiration for Kirrin Castle in some of Enid Blyton's stories.
Pippa Russell, visitor services and enterprise manager at the castle, said: "The ravages of time have begun to catch up with the large pieces of stonework around the keep, many of which lie on their side or upside down where they fell when the castle was blown up by gunpowder in 1646.
"The inner core of these sections is more exposed to the elements than standing walls and this is where much of our remedial work will be focused."
The top part of the castle was closed after frost damage and crumbling stonework prompted health and safety fears in April, this year.
The first phase of the repairs starts next month, and phase two will take place from spring 2007 to summer 2008 with repairs to the keep and south-west gatehouse.
yorkshiretoday.co.uk
