189. RAMPARTS OF AIGUES-MORTES. GATE KNOWN AS THE PORTE DE LA GARDETTE. DRAWBRIDGE. (TO THE RIGHT OF THE DRAWING THE TOUR CONSTANCE, BUILT BY ST. LOUIS)
The gateways of fortified enceintes were modified in the fourteenth century not only by alterations in the plan of towers, the substitution of stone machicolations for the wooden hourds or scaffoldings of parapets, the addition of portcullises, folding-doors, and the machicoulis of the vaulted passage, but further by the invention of the drawbridge. A drawbridge, it may be hardly necessary to say, consisted of a wooden platform suspended by chains to cross-beams poised on uprights on the principle of a see-saw; when lowered, the bridge afforded a passage across the moat. It was raised by depressing the inner ends of the lever-beams which pivoted upon a fulcrum, and thus brought the platform up vertically against the front of the building, where it formed an outer door which an attacking party had either to batter in or to bring down by cutting the chains.
190. RAMPARTS OF DINAN. GATE KNOWN AS THE PORTE DE JERZUAL
It will be readily perceived that such a bridge was infinitely more effectual and more to be depended upon than the portable bridge mentioned in our description of the castle gate of Carcassonne. The latter had to be raised piece by piece, a prolonged operation impossible of execution in case of a sudden surprise.
Aigues-Mortes seems to have been one of the first fortresses to which the new methods were applied. The gates east, west, and south are constructed on the twelfth-century system, as exemplified at Carcassonne. But the northern gate, known as the Porte de la Gardette, which was either made or altered in the fourteenth century, still shows the grooves for the beams of the drawbridge, and the pointed arch of the doorway is enframed by a square rebate destined for the platform when raised.
The use of drawbridges became very general in the fourteenth century, and gave rise to various ingenious combinations. The gate at Dinan, known as the Porte de Jerzual, which probably dates from the close of the century, is a curious example. It is not placed between two towers in the manner then usual, but is pierced through the actual face of a tower. In this case, the inner prolongation of the lever-beams formed a solid panel like the platform of the bridge itself. It was worked through a hole in the roof of the entrance archway, being raised with the help of a chain, and falling through its own preponderant weight. The horizontal pivot on which it turned rested on the brackets shown in [Fig. 190]; the external sections of the lever-beams sank in the usual manner into the vertical grooves above the arch, and when the bridge was up, the solid panel joining the inner ends of the levers doubled the protection it gave. In case of alarm, the chain had simply to be let go, and the panel falling by its own weight, the bridge rose, and the barricade was complete.
191. VITRÉ CASTLE. GATE-HOUSE
By the fifteenth century drawbridges were in universal use; an interesting development was the result. This was the introduction of a smaller gate or postern in the curtain between the towers, by the side of the great gateway. Each of the two apertures was furnished with its own drawbridge. That of the centre, which was reserved for horsemen and vehicles, was worked by two beams or arms, as we have seen, while the smaller footbridge of the postern was raised by means of a single beam, the chain of which was attached to a forked upright.