George Thomas Clark, Mediæval Military Architecture in England…
“ In claiming for these moated mounds a northern and in Britain an English origin it would be too much to assert that in no other class of works is the mound employed, or by no other people than the Northmen; but it may be safely laid down that in no other class of early fortification does the mound occur as the leading and typical feature. In Roman and Norman, and possibly in purely British works, the mound may be occasionally seen, like the cavalier in the works of Vauban, as at Kenilworth, or as an outwork, as at Caerphilly, or it may be employed to cover or divide an entrance ”
