Out of this list of eighty-four castles we shall find that no less than seventy-one have or had mottes. The exceptions are the Tower of London, Colchester, Pevensey, and Chepstow, where a stone keep was part of the original design, and a motte was therefore unnecessary: Bamborough, Peak, and Tynemouth, where the site was sufficiently defended by precipices: Carlisle and Richmond, whose original design is unknown to us: Belvoir, Dover, Exeter, and Monmouth, which might on many grounds be counted as motte-castles, but as the evidence is not conclusive, we do not mark them as such; but even if we leave them out, with the other exceptions, we shall find that nearly 86 per cent. of our list of castles of the 11th century are of the motte-and-bailey type. About forty-three of these castles are attached to towns. Of these, less than a third are placed inside the Roman walls or the Saxon or Danish earthworks of the towns, while at least two-thirds are wholly or partly outside these enclosures.[244] This circumstance is important, because the position outside the town indicates the mistrust of an invader, not the confidence of a native prince. In the only two cases where we know anything of the position of the residence of the Saxon kings we find it in the middle of the city.[245] Even when the castle is inside the town walls it is almost invariably close to the walls, so that an escape into the country might always be possible.[246] Of the towns or manors in which these castles were situated, Domesday Book gives us the value in King Edward's and King William's time in sixty-two instances. In forty-five cases the value has risen; in twelve it has fallen; in five it is stationary. Evidently something has caused a great increase of prosperity in these cases, and it can hardly be anything else than the impetus given to trade through the security afforded by a Norman castle. Our list shows that Mr Clark's confident statement, that the moated mounds were the centres of large and important estates in Saxon times, was a dream. Out of forty-one mottes in country districts, thirty-six are found in places which were quite insignificant in King Edward's day, and only five can be said to occupy the centres of important Saxon manors.[247]