by John Mosier
But the French had a substantially higher percentage of men in elite units. In addition to the infanterie coloniale, they had 30 battalions of chasseurs and chasseurs alpins. Although technically battalions, and oftentimes treated by military historians as “light” infantry or “riflemen,” in France the chasseurs were more heavily armed than regular infantry units, and operated at a much higher peacetime strength. As a group, they were the best soldiers France had.
The difficulty was that almost all of them were south of Paris, and, not surprisingly, the twelve battalions of mountain troops (the chasseurs alpins) were all in the Alps, that is to say, southwest of Switzerland.
Once again, geography defined crucial elements of national defense policy. Given all these factors, no matter how efficient the mobilization scheme was, it would take weeks to deploy the French army to the frontier. What was required was a way to keep the invaders from penetrating deep into France while the armies were assembled and moved into action.
THE FRENCH SOLUTION
In June 1872, less than a year after the triumph of the Third Republic over the Communards, the government began deliberating on how this problem could be solved. Adolphe Thiers created a Committee of Defense to consider how best to guard the country against a future invasion, and in June 1873, one of France’s outstanding military engineers, Adolfe Séré de Rivières, was appointed secretary to the committee.9
After due deliberation, this body decided that the best solution to the problem was the construction of fortifications at key places on the frontiers, everywhere from Dunkirk to Nice. The system would fulfill two functions (at least): It would block the key invasion routes into France, and it would give the country time to mobilize and deploy its enormous conscript armies.
Born in 1815, Colonel Séré de Rivières had spent his professional career working with fortifications; indeed, in 1868 he had been charged with developing forts around Metz. With his prodding, the council formally renounced the complex geometrical shapes that had been a common feature of forts from the time of Vauban on, laying down the general plan for a much simpler and sturdier design.
Never a nation to pull back from great engineering projects, the council decided not only to protect the three land frontiers, but to protect most of the major cities as well. There was a certain logic to this latter move. The reason Paris had held for months and months in 1870 was owing to the forts that surrounded it. In consequence, cities comfortably distant from the frontier were girded by forts: Nice, Besançon, Lille, Lyons. The double-pronged approach is probably why so many people were confused about Verdun: knowing that other cities in France were protected by forts, it was easy to conclude that the battles for Verdun were for possession of the town.
This was an engineering project on a grand scale indeed. Over the next 35 years the French constructed 504 forts of various sizes, and an additional 278 prepared artillery emplacements.10 No less than 32 forts guarded the gateway of the Meuse.
Given the vast scale of the project, and the widely differing conditions, a description is difficult. The engineers called the forts polygons, and most of them, seen from above, resembled nothing so much as the outline of a small house. There was one feature that was a carryover from the original structures of Vauban and his descendants, Marc-René de Montalembert and François-Nicolas Haxo: the idea of a dry moat and sharply angled walls to render an infantry assault extremely difficult.
However, the new system of forts used a greatly simplified plan, and in the northeast in particular, the forts were largely dug into the reverse slopes of ridges. As might be expected, the designs evolved over the decades, largely in response to the increasing efficacy of artillery, as we shall see in the next chapter.
The French word for fort is the same as the English word, but, like everything else in France, there were specific subclassifications, so the grand total of 504 structures included three separate categories, the basic distinction simply being size: 306 forts (the largest structures), 31 redoutes, and 167 ouvrages. Practically speaking, however, the only distinction was a matter of modernity and size; that is to say, most of the forts were constructed before 1885 (196) and most of the ouvrages were constructed after that point (114).
So technically, nine of the 34 Verdun structures were actually ouvrages, but we can call them all forts without doing violence to the basic idea, since the only real difference was size.
The prepared artillery positions, called batteries, deserve some explanation. Although the forts possessed some artillery, the basic idea, poorly understood, was that the real firepower would reside in the guns emplaced in prepared positions behind the fort itself. So one of the chief tactical functions of the fort was to provide a protective barrier for the gunners, and a shielded observation post from which observers could direct artillery fire.
In the 1870s—and for decades afterward—heavy artillery was not particularly mobile. So the idea was to have the guns already in position, permanently mounted on stable stone and concrete platforms, with the ammunition stored in secure magazines that would minimize catastrophic accidents or lucky hits from enemy gunners.
THE MEUSE AND VERDUN
Before 1871, the quickest route into France for the Germans was the one they took in July 1870. They massed their armies on the 100-kilometer stretch of the border between the two countries, crossed it, and then spread out.
With the new frontier, the German stronghold of Metz was now less than 40 kilometers from what was potentially the most vulnerable point in French territory: the Meuse river valley. When Pétain spoke of Verdun as being the boulevard into France, he was speaking symbolically—in terms of that distinct French term moral—but he was also speaking very literally. The valley is the highway into France.
From the very first days of its meetings, the defense committee realized the importance of blocking the Meuse valley, as it was a logical path of entry into France, and, given the new German frontier, by far the most logical route. The other convenient entry point that led into France, the trouée des Charmes, was a good 100 kilometers farther down, and German armies using it would have to work their way through the Vosges mountains and around the plateau dominated by the city of Nancy. But the stretch of the river above the city of Verdun, all the way up to Stenay (about 45 kilometers), is ideal.
The course of the Meuse is serpentine. It winds its way up from Toul, past Saint-Mihiel, Verdun, Stenay, makes a sharp northwesterly turn around Charleville-Mezières, then curves back to the north, flows through Givet, and then up into Belgium. It goes past Dinant and Namur, now taking a northeasterly course, finally emerging north of Liége as the Maas, where it makes another shift, this time back to the northwest, and flows through the Netherlands to the sea.
Unlike the Rhine, the Meuse is not very wide—although it was a reasonable obstacle for nineteenth-century armies. The land on each side of it, the valley, is surprisingly broad and flat, the average width being about nine kilometers. The chief problem, militarily speaking, is that for most of its course, and particularly from the point at which it curves back to the northwest and up to Sedan, the valley terminates abruptly in steep, forested ridges, the beginnings of the great forest of the Ardennes that sprawls across Luxembourg and southeastern Belgium.
However, in its passage through France, the river resembles nothing so much as a furrow in the ground, as though a giant plow had thrown all the dirt it excavated for the actual channel up onto the banks.
The term forest in this instance is accurate insofar as the trees go, but misleading in that a forest can be on a relatively flat stretch of land. The Ardennes, like its southern continuation the Argonne, is extremely rough territory: bluffs and steep ridges running off at sharp angles. There had been paths through it since time immemorial, and the Romans had built roads, so it was not impassable. But the relatively few passages through it were simply insufficient to support an army of any size.
Fr
om the German point of view, the terrain was unfortunate, because the valley of the Meuse was a perfect superhighway into France and Belgium. In that latter country, the left bank of the river was comparatively flat, the beginnings of a large coastal plain that stretched out to the English Channel. The difficulty was how to get into the valley. So far as Belgium went, there was only one practical entry point: Liège.
The Belgians were quite aware of this. Their army had a great engineer as well, and under the leadership of Henri-Alexis Brialmont, the Belgians surrounded Liège with twelve forts and Namur, 60 kilometers to the southwest, with nine. Brialmont reasoned, correctly enough, that once an invader crossed the Meuse between those two cities, Belgium would be impossible to defend. So the military solution was to make the crossing well-nigh impossible.
The French weakness was more serious. Below Stenay, the terrain flattens out for a 30-kilometer stretch, providing easy access to the valley in both directions. Given the proximity of what in France was known as the trouée de Stenay to the new frontier, the logical move by the Germans would be to get there as quickly as possible and drive south.
The next town upriver from Stenay is Verdun. A short distance north of the town, the landscape changes. On the right bank (the side facing Germany), there is a series of rough, forested ridges stretching all the way down to just south of Saint-Mihiel, about 60 kilometers. This stretch of rugged terrain was called the heights of the Meuse. True enough, but since the same term could be applied to about three-quarters of the right bank (and several stretches of the left bank as well), it is easy to get confused.
However, the point is that the heights of the Meuse, like the Ardennes, was a serious obstacle. Given any choice in the matter, the Germans would head directly for the trouée de Stenay and move south. Because just to the south of Verdun, the countryside opens up, becomes more agricultural, and there are no natural obstacles to stop an advancing army aiming to strike deep into the heart of France.
What made the Meuse so tempting as well as puzzling was that the ground forming the actual valley was generally a plain of decent width, so there were rail lines and highways running alongside the river itself. Anyone who looked at the Meuse could see that it was a wonderful highway bisecting Belgium and running deep into France.
Moreover, there were sizable stretches along the left bank that provided easy access to the interior. Specifically, there was one from just below Stenay that went all the way to Charleville-Mézières, and a second one below Verdun that went all the way down past Saint-Mihiel to Toul.
So basically, if you were the German general staff, you would simply mass a large army north of Metz, tell them to head east, turn south at the river, go upstream for 50 kilometers, then turn west and head for Paris.
There was a reason for the dogleg. The left bank of the Meuse, running all the way down from Belgium and Luxembourg to below Verdun, was a rugged forested area, the southern extension of the Ardennes forest, the Argonne. It was a natural barrier. Although the Romans had cut a road through it, very little had been done since. It was not the sort of area that an army would find easy to pass through, formed a natural barrier.
So an invader would have to move due south once he reached the river.
Their advance through the valley would be further channeled, because the most vulnerable part of the Meuse—from just below Stenay all the way down below Saint-Mihiel—is protected by another natural barrier, known as the côtes de Meuse. Another peculiar French word, côte can mean anything from coast to slope to side, but in this case, the best English word is height. Because the heights of the Meuse were very much that: a series of abrupt ridges and bluffs, occurring at irregular angles to each other and the river itself.
Generally speaking, the area between the Meuse river and its neighbor to the east, the Moselle, is rolling country, ideal for maneuvering. But as one moves west, the côtes are an impressive obstacle. Heavily forested, with irregular buttes rising up to over 350 meters, the ridges flank the right bank of the river to a depth of ten kilometers and sometimes more.
The Heights of the Meuse really have to be seen to be appreciated as obstacles. They lack the dramatic verticals of the Southwestern United States, for instance, but they more than make up for it by their density. Seen from a good vantage point—say, the Autoroute de l’Est just before exit 32 (about twenty kilometers east of Verdun)—they literally stretch all the way across the horizon, a wall of green that gives the impression of being one impenetrable mass. The impression is not an illusion.
Similarly, the trouée de Stenay is an equally dramatic sight, clearly visible after leaving the village of Pillon and heading toward Mangiennes (about 25 kilometers north by northeast of Verdun). Although there is an impressive mass directly ahead, over on the horizon to the right the mass of green simply ends. There’s an opening.
The best way to think of this natural obstacle on the right bank above and below the city of Verdun is to envision it as a miniature Vosges mountain range: not so high, not so wide, not so steep. But as far as armies were concerned, quite steep, and impenetrable enough. Moreover, this 60-kilometer mini–mountain range was in exactly the wrong place, so far as the Germans were concerned. Draw an imaginary line from Saint-Mihiel to Metz. The terrain above the line is wonderful country for mass deployment: nothing but endless rolling fields.
So the solution (von Moltke’s common sense again) would be to come storming out of Lothringen through the trouée de Stenay, head straight down the valley and break out into the interior. Because basically, if you draw another imaginary line, this one from Verdun to Reims, the terrain to the south of it is by and large more of the same rolling country, ideally designed for mass armies.
Now, the French could see this as plainly as the Germans, and indeed one of the first priorities of the defense committee was to block the Meuse. The ideal place for this was at that point where the heights on the right bank and the rugged terrain of the Argonne on the left come closest to the river itself, forming a natural bottleneck.
Now Séré de Rivières was hardly the first Frenchmen to notice this fine natural feature. In fact, there had been a castle there for centuries, and gradually, around the castle, a town: Verdun. But cannon had transformed warfare in one significant way: A castle overlooked by ridges and hills was hardly a defensible proposition, and Verdun, straddling the river itself, was the classic case. Gunpowder made it indefensible, but then again, no one was interested in defending it.
It simply happened to be the closest town to the choke point, because, fortuitously (if you were a French engineer), right above the town, the ridges of the Argonne are more or less perpendicular to the river. The topography simply speaks for itself, and the French began building forts. In 1875 they built five on the right bank, on the heights of the Meuse, and four on the left, on the Argonne ridges closest to the river.
The heights were too good a natural defensive position to ignore, so the engineers laid out a series of forts along the heights to the south. The term used to denote this group of forts was les forts de rideau, rideau being another all-purpose French word that literally means line, but in the sense of a line of trees. A line of obstacles impeding our view, and the forts of the rideau formed a defensive line blocking access to the valley all along the heights.
From Verdun to Toul there were seven of these, six on the right bank, and one on the left, and five of them were located on the 30 kilometer odd stretch of the river between the towns of Verdun and Saint-Mihiel. In consequence, they played a key role in the first battles for Verdun. So, even though they were not, for administrative purposes, part of Verdun, were not part of the camp retranché de Verdun, French accounts of the fighting tend to treat them as though they were. Thus Gabriel Bichet, in writing a monograph entitled “The Role of the Forts in the Battle of Verdun” (and quoted in the opening chapter), begins by describing the bitter fight for the Fort de Troyon in September 1914, even
though Troyon was actually one of the rideau forts and not part of Verdun at all.
The distinction may ludicrously legalistic, but what it speaks to is the point made in the opening chapter of this book: these areas are all closely related, are all part of the same strategic objective, so the battles there are all of one piece.
The forts of the rideau were all completed before 1877, at which point the engineers added two more forts to Verdun.
The easiest way to conceptualize what was going on is to envision a circle, with the town of Verdun at the center. The twelve-o’clock position would be due north, and since the shape is a circle, we can measure it off in degrees, with twelve o’clock being zero degrees.
The first set of forts on the right bank had formed a rough arc from about 10 degrees to about 70, with Belleville being at 10, Tavannes being at 70, the other three forts in between. The next two forts, constructed in 1877, extended the arc to about 160 degrees, the approximate position occupied by Fort Houdainville, to the southeast.
In 1881, three more were added. Vaux, on the right bank, part of a plan to fill in the enormous arc to the northeast, was at about 45 degrees, about nine kilometers to the northeast of the city. The other two were on the left bank.
The 1875 forts on the left bank had all been put to the southwest of the city; that is, they formed a rough arc from about 190 to 250 degrees. There was one exception: Marre, at about 310 degrees, located on one of the Argonne ridges to the northeast of the city. Now the engineers added one fort to the northwest, at about 300 degrees, and seven kilometers from the city. Called the fort Bois Bourrus, it was located on a ridge in the Argonne of the same name.