Colchester Castle is about to undergo a major refurbishment.
The castle, which has the largest Norman keep in Europe, is being emptied of all its exhibits before work starts on installing new displays.
The museum will be closed while the £4.2 million project is carried out. It is expected to re-open for Easter 2014.
Repairs will be made to the roof and heating system, and exhibits will be added to the collections.
ITV News Anglia's Olivia Paterson reports.