ABSTRACT
De la Roncière in his magisterial Histoire de la Marine Française includes a passage in which he lists the 10 principles of naval warfare which can be found, (in his view) in Vegetius’ De Re Militari, book IV. These were widely known to medieval writers; de la Roncière in fact traces them from a crusaders’ manual to the works of Egidius Romanus written for Philip the Fair of France, to Christine de Pisan and, in the fifteenth century, Jean Bueil’s treatise Jouvencel. According to his medieval commentators, Vegetius suggested that burning tow soaked in a flammable substance (pitch, sulphur or oil) should be hurled at the enemy. Lime and dust should be thrown in an attempt to blind an enemy crew who should also be made to slip on decks coated with soft soap, similarly launched onboard in breakable containers. A great beam should be hung from the mast with iron-bound ends so that it could be used like a battering ram. Divers should try to drill holes in the hull of an enemy ship with augers and then stones should be thrown to increase the leaks and speed up its sinking. Rigging should be cut with billhooks and broad arrows fired to make holes in the sails; a weaker ship should be grappled with. Finally every attempt should be made to catch an enemy unprepared and to trap him against the shore while the attacking ship stood out to sea.1 This summary makes no mention of Vegetius’ one suggestion on the deployment of ships in battle; that a fleet should be drawn up in a half moon formation with the strongest vessels on the wings. If an advancing enemy then tries to break the line in the centre, these ships can envelop it.2
