by J E Kauffman
Of the major powers, Germany possessed the newest and most impressive fortresses located in Alsace and Lorraine. According to the Schlieffen Plan, the fortresses of Metz and Diedenhofen (French Thionville) shielded the main route into Lorraine. The fortress of Strasbourg in Alsace, linked to Feste Kaiser Wilhelm II, was mostly a fall-back position for the field army, which was to use the terrain between Metz and the Vosges to delay a French advance and buy time for an unhindered German offensive through Belgium.
German and Russian fortresses in the East.
According to the French Plan XVII, the fortresses of Verdun, Toul, Épinal and Belfort were expected to cover the mobilization of the French army. Several forts linked the fortresses of Verdun and Toul and the fortresses of Épinal and Belfort. The Trouée de Charmes (Charmes Gap), which lay between these two fortress groups, included three river barriers (Vezouze, Meurthe and Moselle) that cut through the plains and rolling hills, the centrally located city of Lunéville and Fort Manonviller, a major fort d’arrêt – a ‘stop’ or blocking fort. According to the plan, the French armies were to advance into Alsace and Lorraine as soon as they assembled. However, Joffre, who expected a German thrust through southern Belgium and Luxembourg, modified the plan before the war.4 After he obtained additional funds for the eastern forts, the army undertook work on older forts near Belgium in the northeast. Unfortunately, it was too little too late.
The Germans also had a string of fortresses on their Eastern Front: Posen (Polish Poznań), Thorn (Polish Toruń) and Graudenz (Polish Grudziądz). Fortress Königsberg served as an anchor on the German left flank with the heavily forested terrain and lakes of East Prussia between it and Graudenz. According to the Schlieffen Plan, the forces in the East would go on the defensive while the bulk of the German army took on the French in the West. The scheme did not work out because the Russians invaded East Prussia, which forced the German high command to transfer a couple of army corps from the Western Front to the East. As it turned out, the Germans repulsed and defeated the Russians before these reinforcements arrived. After his victory at Tannenberg, Hindenburg was forced to strip the East German fortresses of their garrisons to bolster his field forces and prop up the faltering Austrian Front.
Austria’s plans were unclear. Although Italy was a member of the Central Powers, the Austrian high command did not trust it and continued to maintain and improve the forts on their sensitive mountainous border.5 There were few significant permanent fortifications on the frontiers of Austria’s Balkan provinces. There were two major fortress rings to defend the front with Russia in Galicia: Cracow and Przemyśl. Austria’s plans did not dovetail with German strategy on the Eastern Front. Soon after the war broke out, the Austrian command foolishly opted for offensive action, which became a major rout and put a strain on the Germans in the East. The retreating Austrians lost most of Galicia and allowed a Russian army to isolate the fortress of Przemyśl.
The Russians also had a string of fortresses, most of which faced a possible German invasion from East Prussia and stood mainly between Warsaw and Grodno. The Russians planned to use them to cover their mobilization. These fortifications included old and new forts. In 1880, the Russian army prepared a plan for the construction of fortifications on the Narew and Bobra (Polish Biebrza) rivers that included defensive bridgeheads at Zegrze, Pułtusk, Różan, Ostrołęka and Łomża on the Narew River. Łomża’s role required its conversion into a fortress. The fortress of Novogeorgievsk at the confluence of the Vistula and Narew and Fortress Osowiec on the Bobra secured the flanks of this covering line. The bridgehead at Zegrze consisted of a small fourteenth-century fort until 1898 when work began on two earthen positions reinforced with concrete positions on the escarpment above the northern bank of the Narew. The largest fort was an irregularly shaped hexagon with caponiers, observation posts and barracks. A second, but smaller fort, connected to it with a rampart for infantry and an artillery battery. Between 1906 and 1909, the entire position was modernized with new ramparts and additional positions. At Łomża, the Russians built five earthen forts between 1887 and 1889 on the left bank of the Narew and three forts on the right bank above the town. They updated the position after 1901 when they decided to turn Łomża into a fortress. The three forts on the right bank were renovated, provided a pentagonal trace, concrete barracks and a caponier in the gorge, troop shelters on the ramparts and counterscarp caponiers in the frontal ditch. A 1908 plan called for five new forts in an outer girdle on the right bank and the reconstruction of two forts on the left bank. When he took office in March 1909, General Vladimir Suchomlinov, Russian Minister of War from 1909–15, persuaded the Tsar to approve a decree eliminating the ‘fortresses’ in Poland, except for the largest, which included Warsaw, and those located between Novogeorgievsk and Osowiec. The 1909 directive ended work on the Łomża fortifications. In May 1910, plans were made to dismantle and remove the forts, but discussions delayed the process. It appears that the Russian army began restoring many of the fortifications between 1912 and 1913 with the intention of using them as shields during mobilization. Other locations such as Ostrołęka, where two forts defended the bridge over the Narew River, and Pułtusk, which consisted only of earthworks built before the war, were not as impressive. Work began on four forts at Różan on the Narew River in 1899. A fifth was never finished because of the 1909 directive. The Russian engineers opted for trapezoidal designs for two of the forts and rhomboidal for the other two, common shapes for modern fortifications. Construction began in 1902 and the last of the four forts was completed in 1910.
Kovno and Grodno on the Niemen River were built to block an eastward German advance. At Kovno there was a girdle of seven forts begun in 1882 and an eighth added later. A new girdle of twelve forts with supporting positions was under construction in 1912 and was due for completion in 1917. When work stopped in 1915, only one fort had actually been completed. The Russian engineers reinforced most of their forts with concrete in 1915. Grodno, located at the confluence of the Bobra and the Niemen rivers, had seven forts dating from 1887 and from 1900–12. A further fourteen forts and thirty-seven interval positions formed an outer ring around the city. To the southwest of the Bobra, stands the Osowiec fortress, and, surrounded by swamps, it secured the north flank of the line of bridgeheads on the Narew. This impressive position included two forts built between 1882 and 1890 that continually underwent modernization. A further two forts were added after 1900. The final phase of rebuilding began in 1912 with the construction of shrapnel resistant shelters. Additional works constructed between 1913 and 1914 successfully resisted German heavy artillery bombardment.
Novogeorgievsk, the largest of the Russian border fortresses, occupied a strategic location and was as important as Verdun was for the French. The fortress formed an impressive girdle at the confluence of the Vistula and Narew rivers. Originally fortified under Napoleon, construction of its first girdle of forts began in the 1880s. A second girdle was added on the north side of the rivers and a new front on the east side between the two rivers between 1912 and 1915.
Not as modern, but just as large, was Fortress Warsaw, which included a citadel built in the early 1830s and six surrounding forts completed in 1865. The fortress included several generations of nineteenth-century fortifications. After 1883, the Russians built an outer ring of fourteen forts (four on the eastern bank of the Vistula). In 1886, they developed an inner ring of five forts that were completed in 1892 and to which they later added interval positions. By 1900, an enceinte connected the inner ring and over twenty forts formed the inner and outer girdle on the left bank with a wall between the forts of the inner ring. Several forts formed the eastern part of the ring on the right bank. During the 1890s, the girdle of brick forts was modified when the brick was replaced with concrete or the concrete was used to cover brick sections. At this time, the French were carrying out similar renovations on their own forts as well. During a further modernization phase, some of the Russians forts ended up with two se
parate ramparts – one for infantry and the other for artillery – when a lower rampart was added and the length of the glacis was extended. However, despite their generally larger size, the Russian forts of Warsaw and other sites did not equal the fortifications of the West. They had no armoured gun turrets and usually lacked armoured components. The most modern addition to the Russians forts in Poland, beside electricity and communications, took the form of concrete shelters. Fortress Warsaw was included in the decommissioning order of 1909, but the years of indecision that followed prevented the liquidation of that fortress before the war.
The salient formed by Russian Poland faced the threat of a German invasion on the west and north sides and an additional threat from an Austrian incursion in the southwest where the Russians had fewer, smaller and mostly obsolete fortifications. The line of the Vistula formed the main barrier facing west with no major positions to the west of it near the German frontier. The old, bastioned fortress of Ivangorod, built in the second quarter of the nineteenth century, stood almost in the centre of the Vistula line with Warsaw to the north and little else in the way of fortifications to the south. It consisted of seven detached forts built between 1878 and 1882, making it the strongest position south of Warsaw. Further to the south and near the Austrian border, was Zamość, an old fortress that had acquired a circular casemated fort in the 1830s.6 It had been decommissioned in 1866 and sections of its defences were later torn down. Well to the east of Zamość was the fortified town of Dubno with an ancient castle and two forts added in 1900s. Rovno (Polish Rowno) included seven earthen girdle forts from 1890, whereas Lutsk (Polish Łuck), on the Styr River, consisted of four earthen forts from 1890. Dubno, Rovno and Lutsk formed the Volhynian Triangle (a historical region in northwest Ukraine) and covered a possible Austrian invasion from the direction of Lemberg.
The Russian army designated the Bug River as a second line of defence, which covered the route from Brest-Litovsk to Minsk and Moscow. Brest-Litovsk, one of the newest Russian fortresses, was located on the western side of the large Pripet Marshes. The citadel, built on the central island between the 1830s and 1843, was known for its thick, red-brick walls. It was surrounded by three major fortifications, an earthen curtain with several brick casemates that stretched over 6.4km and a wet moat. The Russians added a girdle of ten artillery forts between 1878 and 1888 and modernized these earth-covered, brick forts surrounded with ditches between 1908 and 1911. The renovations consisted of pouring a layer of concrete up to 2m thick over the brick masonry. Between 1909 and 1915, the Russians added fourteen newer concrete forts and thirty interval positions. By 1914, only two of these fourteen forts had actually been completed.
In the late nineteenth century, the Russian army fortified several other sites, including Olita, which guarded a new railroad crossing. The main Russian defensive system included forts and fortresses that defended river crossings and stretched along the Narew and Niemen rivers facing East Prussia. It did not form a continuous line, unless the rivers are included as part of the defences.
The Russian rail system, much improved after the Russo-Japanese War, was more important than the road system, which often turned to mud in heavy rains. The Russians opted for broad gauge rails, which made it difficult for their armies to advance into enemy territory where they encountered the narrow standard gauge rail lines. It was easier for the Germans and the Austrians to use the Russian rail network because they could increase the length of the axles of the rolling stock and engines.7
Most Russian forts were two to three times larger than Austrian forts. Beginning in the 1890s, the Russians, like the other Europeans, started to use concrete in their forts, but they failed to add armoured components. In 1909, their army ceased work on their Polish fortresses, but maintained Novogeorgievsk and Osowiec. The modernization of the outer ring of Novogeorgievsk was not completed in time for the First World War. The Russian army quickly brought the decommissioned fortifications back into service at the onset of the conflict. The fortresses served as ammunition depots and artillery parks for almost all the Russian heavy artillery. This might have been a reasonable decision if the Russians had not found it difficult to distribute these resources in 1914 and 1915. In addition, when these sites fell into enemy hands, they contained vast amounts of weapons and munitions, which came as a boon to the Germans and the Austrians who suffered from shortages in 1914 and later.
There was a marked difference between the way the Russians used forts and fortresses and the French did. The French created a major fortified line that extended from Verdun to Belfort with only one significant gap of about 40km (25 miles), which, nevertheless, did include a few forts. The line consisted of two major segments of about 95km (60 miles) in length each. The entire line, including the gap, extended for about 230km (145 miles) and covered almost the whole front between France and Germany. The major fortresses of Russia, on the other hand, were 95km (60 miles) to over 240km (150 miles) apart and some controlled key points on major invasion routes. The only position that resembled a fortified line ran along the Narew, Bobra and Niemen rivers for about 360km (225 miles) and was thus almost 50 per cent longer than the main French line. In the Russian river line, the gap between the small fortresses was often 65km (40 miles) long or more, which was larger than the single gap in the French line. The entire Russian frontier with Germany and Austria-Hungary was huge and it would have been impractical if not impossible to create a fortified line long enough to hold, especially in terms of nineteenth-century military thinking. The Russians, therefore, had to adopt a policy similar to the one followed by the Germans and the Austrians when it came to forts and fortresses rather than the French one. The Russian forts could do little more than guard key sites, serve as points from which to organize a general defence or function as bases for offensive operations. They were not able to present a solid fortified line that sealed an entire front. By nineteenth-century military standards, this was a reasonable mission, but it also required Russia to have an army capable of manoeuvring and engaging the enemy beyond the fortified sites. The only problem with this strategy was that by 1914 armies were larger than at any time before. The ability to manoeuvre, supply and even arm such large military forces required a highly industrialized nation with great resources. This meant that Germany and France were much better able than Russia to direct huge armed forces.
Artillery and Turrets
What turned most modern forts into formidable positions was their protected artillery in armoured casemates and turret positions. The first requirement of an effective armoured gun turret is a breech-loading gun. In 1872, Charles de Bange, a French artillery colonel, designed the first successful breech system for cannons that prevented gases from escaping from the breech and injuring the crew. The ‘De Bange System’ 155mm L Mle 1877 was adopted by the army. The gun had to be pushed back into position after each firing, like most artillery of the day.
The most effective recoil system appeared on the French 75mm Mle 1897. The French ‘Soixante-quinze’ remained in position after firing while only the barrel recoiled on its carriage and returned to the firing position. The Nordenfeld breech mechanism allowed the gun to fire up to twenty-eight rounds a minute. In 1914, General Frédéric-Georges Herr cited an official document according to which the 75mm gun ‘suffices for all the missions that can be intrusted to artillery in field warfare’. As an artillery officer, he decried the fact that long-range artillery was undervalued in France because it required direct observation, but then the best optical equipment available was limited to distances below 5,000m. The use of aircraft or balloons in reconnaissance and observation, he pointed out, was not even taken into consideration.8
In 1915, the French artillery service still relied mostly on direct-fire guns and was short of heavy artillery, which led to the removal of artillery from the forts in the autumn. Among these weapons, there were a number of old 155mm guns with no effective recoil system. The field army lacked modern indirect-fire weapons and the forts ha
d a few obsolete mortars. Turret guns needed some type of recoil system because space limitations precluded kickback upon firing.
In the 1870s, Captain Henri Mougin developed the first approved turret for the French forts.9 The Mougin Mle 1876 turret mounted two de Bange 155mm L (long barrel) Mle 1877 guns and had embrasures cut in its cupola. Descriptions of the turret vary between sources. According to an article of 20 January 1900 in Scientific American (Supplement, No. 1255), the sides of this wrought-iron turret were 60cm thick and its roof was 20cm thick. The cupola was made of five sections and the dome stood about 1.5m high. An armoured glacis consisting of several pieces formed a collar that surrounded the turret and was set in a layer of concrete, which also protected the subterranean masonry structure. It took eighteen men in teams of six to manoeuvre the turret manually until 1883 when a coal-fired steam engine took over this function. The army adopted the Mougin turret (built at St Chamond) in the 1880s. Mougin modified the design of the turret he presented at the Bucharest tests in 1886. The tests showed that repeated hits on the same section almost destroyed the armour. On the other hand, the French turret fired twice as fast as the German. There were twenty-five of these turrets in service including nine in forts of the main line facing the German border. In the 1900s, some of the turrets were removed and the masonry of their subterranean positions was replaced with concrete or reinforced concrete. German heavy artillery demolished a few forts with Mougin turrets at Maubeuge and Fort Manonviller in 1914.10