The Beaumont family lasted for five or six generations. and it was during this period that the wooden structure on top of the mound was replaced by a stone shell keep. This keep was removed and can now no longer be seen. The wooden palisade around the bailey was probably replaced by stone walls at the same time.
Thomas Beaumont died in 1242 without an heir so the castle became the property of his sister Margaret. Margaret married John du Plessis who then became the new Earl of Warwick. John and Margaret did not have any children to pass the castle down to so it went to William Mauduit, Margaret's newphew. It was during William's ownership of the castle and during the Baron's War that Simon de Montfort's forces attacked the castle and kidnapped the Earl and his wife. The castle suffered a lot of damage during the attack. William was released after paying a ransom but died shortly afterwards. The castle then went to his sister's son, William de Beauchamp.
The Beauchamp family was to own the castle for almost 200 years. After the attack during the Baron's War the castle needed rebuilding and the Beauchamps did that. In the late fourteenth century several major changes were made to the castle including the great hall and domestic ranges, a water gate, improvements to the main gatehouse and the barbican in front of it. Two Beauchamp Earls were called Thomas. Each one was responsible for one of the large towers that were erected on the outer wall. Caesar's Tower came first followed by Guy's Tower. Both towers are much taller than the outer walls. Guy's Tower is 128 feet high and was named after an earlier Earl of Warwick, Guy de Beauchamp. Caesar's Tower is even taller at 147 feet high. The last member of the Beauchamp family to own Warwick Castle was Henry Beauchamp who was the first to be given the title Duke of Warwick. Henry died in his early twenties in 1446 and the castle passed into the hands of his sister Anne Beauchamp who married Richard Neville, 'The Kingmaker'.
Richard Neville, the 'Kingmaker' was one of the most powerful men of his time. He fought alongside Edward IV and the house of York during the Wars of the Roses against Henry VI. In the end Richard and Edward became enemies and in 1471 the Kingmaker was killed at the battle of Barnet. After Richard's death the castle passed into the hands of George Plantagenet, Duke of Clarence as he had married Richard Neville's eldest daughter. George was executed in 1478 and the castle passed to his young son Edward. As a potential heir to the English throne Edward was arrested and placed in prison and later executed. At this point the castle became royal property during the reigns of both Henry VII and Henry VIII.
Over the centuries the castle became an important seat of power and was the home for the Earls of Warwick who played an important role in shaping the history of England. Richard Neville, Earl of Warwick was known as the 'Kingmaker' for his involvement in bringing Edward IV to the throne. The castle is possibly the best castle to visit in Britain due to the wide range of events and attractions that can be seen.