In Roy. MS. 20, D. i., of about the close of this century, the wooden Tower occurs in several of the miniatures. It is constructed in the manner of a scaffolding, having at the top an open platform filled with archers: its height, that of the city walls, close to which it is placed. Examples will be found on folios 305, 306 and 317. The besieged, when they were able to discover the point to which the assaulting tower was to be moved, loosened the soil in that spot by digging; so that, when the ponderous machine arrived, it was overturned by its fore-wheels sinking into the soft earth[416]. The _Chat-Chastel_ combined the _beffroi_ and the _cattus_. But the best account that can be offered of the Siege operations of this time, is furnished by a cotemporary writer, the Seneschal of Carcassone; himself the commander of the defending forces. This very curious document is preserved in the Archives of France, and has been published in the _Bibliothèque de l'École des Chartes_, vol. vii. p. 363. Carcassone was besieged in the autumn of 1240 by the son of the Vicomte de Béziers; and the defender of the city, Guillaume des Ormes, sends to Queen Blanche, regent of the kingdom during the absence of Saint Louis, an exact account of the proceedings. Carcassone was surrounded with a double wall, furnished as usual with towers, and having several barbicans in advance of its various gates. The object of the Barbican was to afford the besieged the means of a flanking attack: it was formed something like a street, with a wall on each side, terminating in a kind of open tower: and it thus became necessary that the enemy should act in the first instance against this outwork; for, by assaulting the curtain, they would be exposed to a flank attack from the barbican, and might also be assailed in the rear by sorties from the head of the work. "To his most excellent and highly illustrious mistress, Blanche, by the grace of God, Queen of the French, William des Ormes, Seneschal of Carcassone, her humble and devoted servant, greeting and faithful service.