The castellan's principal tower should be able to strike all the other towers and places within the castle's enclosure, and to drive out its occupants. [It should command] the provisions. The rooms and dwellings should be kept safe, and relief assured, so that they are not obstructed by those within. The entrances to the principal tower should be so arranged that a feigned relieving force can be held prisoner at the castellan's requisition. The principal tower must have a spiral staircase from the summit to the bottom, with a narrow shaft, which opens onto all the rooms that can be entered by such a stair. The first room at the bottom of the tower should be laid out as a cellar for wine and firewood. The second, above it, will be for the mill and the store of grain, vinegar, salt, salted meat and oil, and for the oven. In the third room let there be the munitions for attack and defence, and also the saltpetre, sulphur and charcoal, which, if kept in the form of wood, may be stored elsewhere, provided it is not damp. Above these let there be one or more prisons, on the same floor as the castellan's room. And if there are more rooms, let them all be for his use. In the middle of the topmost room let there be a store of powder, which should be girt with double walls, 2 and a half feet apart from one another. And the doors through which one enters to this powder should not face one another, so that fire cannot easily be thrown in. And above it should be vaulted, so that, the roof being of timber, the fire that might be thrown with a weight onto the roof does not break the covering and burn the wood. And even if the fire does catch there, it cannot destroy the tower, being at the summit. The aforesaid shaft should have channels that open onto the rooms of the provisioned men, who cannot draw water anywhere else. And thus, at his pleasure, he can give and withhold water from his provisioned men, so that he alone, with his trusted men, remains free lord of the whole fortress. Let the mouths of the waters be closed with keys, which lock and open the channels, so that the provisioned men outside, raising the water, cannot dam it back poisoned and put it back into the cistern or well. Let the privies be made as far from the well or cistern as possible, and made in such a way that they little obstruct the tower, and let every room have its own. The tower, scarped all around, should have a small recess through which the relief passes, and be so arranged that his household, that is the castellan's, cannot enter it, that is the provisioned men. The door of such a recess should face the rooms of the keep, or else be so placed that those outside cannot strike it. The windows should be gratings of thick iron bars, and be of 2 gratings, 2 feet apart from one another. The stair that [goes] up to the [Continues on fol. 93 verso]