What is the oldest intact castle in England?
That's actually a rather difficult question, since castles tend to be built and rebuilt over time as weapons and defence tactics develop.
We have a number of superb intact castles, like Arundel, Warwick, Windsor, Alnwick, Dover and the Tower of London. All of those date back to the Norman conquest, and have been used and lived in ever since.
Not that the Norman part of the castle has always survived. At Warwick Castle, for example, all that's left of the original Norman keep is the motte, or castle mound. The keep is long gone.
But there's one castle that still proudly displays its Norman roots. The White Tower, the heart of the Tower of London, was begun by William the Conqueror shortly after his coronation. Built from pale Caen stone, it always stood out, proclaiming Norman rule over the city of London. When you visit it, you can see the way the first Norman owners lived. You can even visit the chapel where William the Conqueror once prayed.
Since William's reign, the Tower has been the English monarch's residence, a menagerie, prison and place of execution, and a vault to guard the nation's treasures, like the crown jewels. It's been changed, remodelled and added to - but it's an intact working castle. One that goes back right to 1066 and the first years after the Norman conquest.
If you want to know more about English castles, check out this book by Allan Brown, which is available from amazon.
It's a great book, full of lots of interesting information about the use of castles, which was not all warfare. While initially purely defensive, eventually English castles became homes and finally status symbols - and just looking at a castle or castle ruin can tell you a lot about its age and the reason it was built for.