Many of these buildings which date from the close of the century were remarkable for their ingenuity of arrangement and richness of decoration. But though worthy of all attention from the artistic point of view, they do not come within the scope of our present study--that of _military_ architecture in the Gothic period. CHAPTER III GATES AND BRIDGES Though confining ourselves to a brief historical abstract of the so-called Gothic period in architecture, without reference to Roman examples, we have said enough in the foregoing studies on castles and keeps, and the circumvallation of towns, to give some idea of the importance attached by architects to the gates which secured the _enceintes_, and the bridges which afforded an approach. _Gates._--Following the example of those Frankish architects whose works in Syria after the first Crusade seem to have exercised such far-reaching influence, French builders of the reigns of Philip Augustus and St. Louis reduced the entrances of fortresses and fortified _enceintes_ to the smallest number practicable. Their construction was based upon a system calculated to repulse any ordinary attempt to carry the place by direct attack; as a rule, fortresses were taken rather by ruse, surprise, or treason than by regular siege. [Illustration: 186. CITY OF CARCASSONNE. GATE-HOUSE OF THE CASTLE] During the twelfth, and more especially the thirteenth century, the gates were the points most strongly fortified. They were approached over a bridge, by raising a movable portion of which, however, entrance might be barred on the very threshold. The narrow gateway passage was defended by two projecting towers pierced with loopholes, and connected by a curtain. The whole structure formed a fortified gate-house, known as a _châtelet_, which had to be carried before an assailant could penetrate to the fortress beyond. The passage was further defended by a single or double portcullis, a grated timber framework like a harrow, cased with iron, the uprights of which were spiked at the bottom. The passage was also defended by machicolations or holes in the roof, through which the garrison could hurl down missiles on the heads of their enemies, should the latter have forced the gate. The castle-gate of Carcassonne which was built about 1120 still exists, and is a good example of such arrangements. The minute precautions adopted by architects to guard against surprise are very manifest in this example. A sudden attempt was often successful, especially if favoured by traitors among the defenders themselves.