Lewes Priory was founded in 1081 by Williame de Warenne
The ruins of a medieval priory in East Sussex are to be transformed into a visitor attraction with lottery money.
The 11th Century Lewes Priory has been awarded £545,500 from the Heritage Lottery Fund (HLF).
The Grade I listed Norman property in Cockshut Road is described by HLF as "one of the most important historical buildings in south-east England".
The grant covers 75% of the cost of the two-year project to conserve the ruins and make them safe for visitors.
Battle of Hastings
The rest of the money has already been secured from other sources including English Heritage and Lewes Town Council.
Access to the site will also be improved and information boards will be installed within the next year.
John Lawrence, chairman of the volunteer-run Priory Trust, said: "This is a massive gain for the town of Lewes."
The Scheduled Ancient Monument was founded as a Cluniac Monastery in 1081 by Williame de Warenne and his wife Gundrada.
He was a Norman who fought at the Battle of Hastings in 1066 with William the Conqueror.
Kate Hickmott, from Lewes Priory Trust, said they were 'absolutely delighted'
During the Battle of Lewes King Henry III based himself at the priory where he negotiated the Mise of Lewes with Simon de Montfort.
The priory was demolished under the orders of Thomas Cromwell and much of its stonework was used in buildings in Lewes.
Stuart McLeod, head of the Heritage Lottery Fund in the South East, said: "This is one of the most important historical and archaeological sites in the South East - on a par with Lewes Castle.
"However, with little interpretation for locals or visitors to understand the sites' rich history, and it currently being fenced off as unsafe, this much-needed award from HLF will provide a bright future for Lewes Priory for generations to come."