Liege, at the outbreak of the war, was a place of great wealth and extreme poverty—a Liege artisan considered himself in prosperity on $5 a week. It was of the first strategic importance to Belgium. Its situation was that of a natural fortress, barring the advance of a German army.
The defenses of Liege were hardly worth an enemy's gunfire before 1890. They had consisted of a single fort on the Meuse right bank, and the citadel crowning the heights of the old town. But subsequently the Belgian Chamber voted the necessary sums for fortifying Liege and Namur on the latest principles. From the plans submitted, the one finally decided upon was that of the famous Belgian military engineer Henri Alexis Brialmont. His design was a circle of detached forts, already approved by German engineers as best securing a city within from bombardment. With regard to Liege and Namur particularly, Brialmont held that his plan would make passages of the Meuse at those places impregnable to an enemy.
When the German army stood before Liege on this fourth day of August, in 1914, the circumference of the detached forts was thirty-one miles with about two or three miles between them, and at an average of five miles from the city. Each fort was constructed on a new model to withstand the highest range and power of offensive artillery forecast in the last decade of the nineteenth century. When completed they presented the form of an armored mushroom, thrust upward from a mound by subterranean machinery. The elevation of the cupola in action disclosed no more of its surface than was necessary for the firing of the guns. The mounds were turfed and so inconspicuous that in times of peace sheep grazed over them. In Brialmont's original plan each fort was to be connected by infantry trenches with sunken emplacements for light artillery, but this important part of his design was relegated to the dangerous hour of a threatening enemy. This work was undertaken too late before the onsweep of the Germans. Instead, Brialmont's single weak detail in surrounding each fort with an infantry platform was tenaciously preserved long after its uselessness must have been apparent. Thus Liege was made a ring fortress to distinguish it from the former latest pattern of earth ramparts and outworks.
Six major and six minor of these forts encircled Liege. From north to south, beginning with those facing the German frontier, their names ran as follows: Barchon, Evegnée, Fleron, Chaudfontaine, Embourg, Boncelles, Flemalle, Hollogne, Loncin, Lantin, Liers, and Pontisse. The armaments of the forts consisted of 6-inch and 4.7-inch guns, with 8-inch mortars and quick firers. They were in the relative number of two, four, two and four for the major forts, and two, two, one and three for the minor fortins, as such were termed. The grand total was estimated at 400 pieces. In their confined underground quarters the garrisons, even of the major forts, did not exceed eighty men from the engineer, artillery and infantry branches of the service. Between Fort Pontisse and the Dutch frontier was less than six miles.
This bridge over the Meuse at Liege was blown up by the Belgians to delay the German advance. The German army crossed on pontoon bridges.
It was through this otherwise undefended gap that Von Kluck purposed to advance his German army after the presumed immediate fall of Liege, to that end having seized the Meuse crossing at Visé. The railway line to Aix-la-Chapelle was dominated by Fort Fleron, while the minor Forts Chaudfontaine and Embourg, to the south, commanded the trunk line by way of Liege into Belgium. On the plateau, above Liege, Fort Loncin held the railway junction of Ans and the lines running from Liege north and west. Finally, the forts were not constructed on a geometric circle, but in such manner that the fire of any two was calculated to hold an enemy at bay should a third between them fall. This was probably an accurate theory before German guns of an unimagined caliber and range were brought into action.
In command of the Belgian forts at Liege was General Leman. He had served under Brialmont, and was pronounced a serious and efficient officer. He was a zealous military student, physically extremely active, and constantly on the watch for any relaxation of discipline. These qualities enabled him to grasp at the outset the weakness of his position.
If the Germans believed the refusal to grant a free passage for their armies through Belgium to be little more than a diplomatic protest, it would seem the Belgian Government was equally mistaken in doubting the Germans would force a way through an international treaty of Belgian neutrality. Consequently, the German crossing of the frontier discovered Belgium with her mobilization but half complete, mainly on a line for the defense of Brussels and Antwerp. It had been estimated by Brialmont that 75,000 men of all arms were necessary for the defense of Liege on a war footing, probably 35,000 was the total force hastily gathered in the emergency to withstand the German assault on the fortifications. It included the Civic Guard.