This point, Vierzon, is an important one to note in the march. The town lies just to the south of a curious district very little known to English travellers, or, for that matter, to the French themselves. It is a district called the "Sologne," that is, the "Solitarium" or "Desert." For a space of something like forty miles by sixty a great isolated area of wild, almost uncultivatable, land intervenes between the valley of the Cher and that of the Loire. Only one road of importance traverses it, that coming from Paris and Orleans, and making across the waste for Vierzon to the south. No town of any size is discoverable in this desolate region of stagnant pools, scrub, low forest, and hunters. It was such a situation on the outer edge of the Sologne which made Vierzon the outpost of Aquitaine, and having reached Vierzon, the Prince, in so far as he was concerned with emphasising the Plantagenet claim over Aquitaine, had reached his northern term. But his raid had, as we know, another object: that of drawing the French forces southward. And, with the characteristic indecision of feudal strategic aims, it occurred to the Black Prince at this stage to immix with that object an alternative, and to see whether he could not get across the Loire to join Lancaster's force, which was campaigning in the West of France on the other side of that river. At Vierzon Edward's men came across the first resistance. A handful of John's forces, irregulars hired by the French king under a leader most charmingly named "Grey Mutton," skirmished to their disadvantage against the Anglo-Gascon force. The Black Prince made back westward after "Grey Mutton," thinking, perhaps, to cross the Loire at Blois, and two days out from Vierzon (rather over twenty miles) he made the only assault upon fortifications which he permitted his men in the whole campaign. This was an attack upon the Castle of Romorantin, in which "Grey Mutton" had taken refuge. It was not the moment for delay. Edward knew that the French army must now be somewhere in the neighbourhood; he had already touched lance with one small French force; but he had his teeth into the business and would not let go his hold. The outworks were taken early in the affair. The keep held out for four days more, surrendering at last to fire upon the 3rd of September.