Indeed, fortification evolved into its own style, and the turrets and sharply vertical emphasis of Scottish Baronial mansions are among Scotland's most unique contributions to British architecture. The first known house in Scotland with these features is Cragside near North Berwick, built by Sir William Bruce for himself and his family in 1666. It is a large, L-shaped stone structure with walls about five feet thick and a tall slate roof with crossbeams. The entrance front has been praised for its elegance and simplicity. The term "Scottish baronial" has been used to describe many buildings across Britain that share similar characteristics. These include tower houses, which were often found in northern England; and great houses, which can be seen in the south of England. But the word "barony" only applies to those buildings belonging to the Barons who ruled Scotland between 1054 and 1314. Before this time, there were only kingdoms or lordships, which were not allocated names until later when they were granted to people by kings or princes. So, although Scotland had many castles built by nobles, these were not called "Barons' castles" but rather just "castles." After the collapse of the Roman Empire in Europe, the British Isles were largely abandoned by central European settlers.