The following centuries saw destruction and reconstruction at the castle due to internal conflicts in Northumbria but also from the Vikings who attacked the north east coast stealing from the vunerable monasteries and murdering the monks. After the Norman invasion Bamburgh played an important part in protecting England from the Scots and major rebuilding work took place to improve the defences of the castle. In 1164 during the reign of Henry II a large square Norman keep known as the 'Great Tower' was built at the castle at the cost of four pounds and over the next few centuries the castle was visited by all the English kings.
The War of the Roses saw the end of Bamburgh Castle's power when a siege was ended with the use of cannons, the first English castle to fall in this way. The following centuries saw the decline of the castle's fabric as repair costs grew too much for the private owners to afford. This state of disrepair lasted until 1894 when the castle was bought by Lord Armstrong who began restoration work to convert the remains into a private mansion. The results of his and successors work is what you see today when you visit Bamburgh castle.