This style was long followed in England. It is known as the baronial, and architects in all parts of the country, when building a modern mansion in the castellated manner, have invariably followed it. It is easy to see, however, that it was early abandoned in Scotland, the people not taking their forms of architecture from a nation with which they had no connection but that of hostility. The first species of national baronial architecture to which they resorted was a very simple one, characteristic of an impoverished people. It consisted of little more than four stone walls, forming what in fortification is called a blockhouse. The walls were extremely thick, with few apertures, and these suspiciously small. But these old towers or keeps were not without some scientific preparations for defence. In the more ancient baronial castles, the large square or round towers at the angles served to flank the walls or curtains between them; that is, supposing an enemy to be approaching the main gate, he could be attacked on either side from the towers at the angles. To serve the same purpose, the Scottish keeps had small bastions or turrets at the corners, which, projecting over the wall, flanked it on each face. The simple expedient here adopted is at the root of all the complex devices of fortification. The main thing is just to build a strong edifice, and then, by flanking outworks, to prevent an enemy from getting up to it. In other respects, these square towers were scarcely to be considered peculiarly Scottish. They are to be found in all parts of the world--along the Wall of China; in the Russian steppes; in Italy, where they are sometimes remains of republican Rome; and in Central India. They constitute, in fact, the most primitive form of a fortified house.