We approach the military problem of 1793, therefore, with the following two fields clear before us:—
1. In the north-east an advance on Paris, the way to which is blocked by a quadrilateral of fortresses: Mons, Maubeuge, Condé, and Valenciennes, with the subsidiary stronghold of Lequesnoy in the neighbourhood of the last. Mons has been in Austrian hands since Dumouriez’ retreat; Condé is just cut off from Valenciennes by Coburg’s advance, but has not fallen; Valenciennes and the neighbouring Lequesnoy are still intact, and so is Maubeuge. All must be reduced before the advance on Paris can begin. Behind these fortresses is a French army incapable as yet of attacking Coburg’s command with any hope of success. Such is the position in the last fortnight of April.
2. Meanwhile, on the Rhine the French garrison in Mayence is besieged; Custine, the French commander in that quarter, has fallen back on the French town of Landau, and is drawing up what are known in history as the Lines of Weissembourg. The accompanying sketch map explains their importance. Reposing upon the two obstacles of the river on the right and the mountains on the left, they fulfilled precisely the same functions as a fortress; and those functions we have just described. Until these lines were carried, the whole of Alsace may be regarded as a fortress defended by the mountains and the river on two sides, and by the Lines of Weissembourg on the third.
