 His famous Edwardian concentric castles, large stoneworks with multiple rings of defences, grew up at strategic locations throughout the north and the local populace was placed securely under English authority.In this case, encastellation was the result, not of weak central authority, but of a strong royal hand and direction.In Scotland, the spread of castles came with the Normans who, in the twelfth century, began constructing castles of the motte-and-bailey type in the south, where they received royal support, especially in Galloway.