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. [Illustration: 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. [Illustration: 192. ENCEINTE OF GUÉRANDE. GATE OF ST. MICHEL] The castle of Vitré, which was built, or at least completed at the close of the fourteenth or beginning of the fifteenth century, illustrates the system in the gateway of its _châtelet_. The gate-house, known as the _Porte St. Michel_, at Guérande, which was built together with the _enceinte_ by John V., Duke of Brittany, in 1431, still preserves the lateral grooves which indicate the shape and arrangement of the postern drawbridge. When raised, the two drawbridges closed the apertures of gateway and postern, while the open gulf of the great ditch, either empty, or full of water, cut off the approach to the entrance.