Having now sketched the composition of the English forces, let us move forthwith to the scene of action. We must omit the early incidents of the war, and the assumption by Edward of the famous motto wherein he consecrated his claim to the crown of France, _Dieu et mon droit_. We must pass by the famous naval action of Sluys, where the English commanders in their zeal to follow the precepts of Vegetius, thought it more important to have the sun in the enemy's eyes than the wind in their own favour, and where the archers, acting as marine sharp-shooters, were the true authors of the English victory. We must overlook likewise the innumerable sieges, even that of Quesnoy, where the English first came under the fire of cannon, merely remarking that owing to their ignorance of that particular branch of warfare, the English were uniformly unsuccessful; and we must come straight to the year 1345, when Henry of Lancaster, Earl of Derby, landed at Bayonne with a force of three thousand men for a campaign in Gascony and Guienne. The name of our first artillery-officer has been given; attention must now be called to our first engineer, this same Earl of Derby, who had lately been recalled from service with the Spaniards against the Moors at the siege of Algesiras, and was the first man who taught the English how to take a fortified town. [Sidenote: 1346, June.] Derby then with his little army harried Gascony and Guienne for a time, until the arrival of a superior French force compelled him to retire and gave him much ado to defend himself. Accordingly, in June 1346 Edward the Third impressed a fleet of innumerable small vessels, none of them exceeding sixty tons burden, embarked thereon four thousand men-at-arms, ten thousand archers and five or six thousand Welsh spearmen, and sailed for the coast of France. On the 12th of July he put into St. Vaast de la Hogue, a little to the east of Cherbourg, dispersed a French force that was stationed to oppose him, and successfully effected his landing. Six days were allowed to recruit men and horses after the voyage, and the army then moved eastward to the Seine, leaving a broad line of ruin and desolation in its wake, and advanced up the left bank of the river. King Philip of France had meanwhile collected an army at Rouen, whence he marched parallel to the English along the right bank of the Seine, crossed it at Paris, and stood ready to fall upon Edward if he should strike southward to Guienne. But Edward's plans were of the vaguest; his diversion had already relieved Derby, and he now crossed the Seine at Poissy and struck northward as if for Flanders. Philip no sooner divined his purpose than he too hastened northward, outmarched the English, crossed the Somme at Amiens, gave orders for the occupation of every bridge and ford by which the English could pass the river, and then recrossing marched straight upon Edward's right flank.