Eastern Front ( World War I ) During World War I , the Eastern Front ( sometimes called the " Second Fatherland War " in Russian sources ) was a theatre of operations that encompassed at its greatest extent the entire frontier between the Russian Empire and Romania on one side and the Austro - Hungarian Empire , Bulgaria and Germany on the other . It stretched from the Baltic Sea in the north to the Black Sea in the south , included most of Eastern Europe and stretched deep into Central Europe as well . The term contrasts with " Western Front " . Despite the geographical separation , events in all the European theatres strongly influenced one another . In 1914 , the Russians ' invasion of Galicia relieved the pressure on the Serbian Front , and in 1916 , the Brusilov Offensive was intended to do the same for the Italian Front . Ultimately , both times the Russians ignored the German forces to their north , which resulted in them over - stretching their supply lines , then suffering further defeats against superior German artillery . Geography . The front in the east was much longer than that in the west . The theatre of war was roughly delimited by the Baltic Sea in the west and Minsk in the east , and Saint Petersburg in the north and the Black Sea in the south , a distance of more than . This had a drastic effect on the nature of the warfare . While World War I on the Western Front developed into trench warfare , the battle lines on the Eastern Front were much more fluid and trenches never truly developed . This was because the greater length of the front ensured that the density of soldiers in the line was lower so the line was easier to break . Once broken , the sparse communication networks made it difficult for the defender to rush reinforcements to the rupture in the line , mounting rapid counteroffensives to seal off any breakthrough . 1914 . At the outbreak of the war , Tsar Nicholas II appointed his cousin , Grand Duke Nicholas , as Commander - in - Chief of the Imperial Russian Army . On mobilization , the Russian army totaled some 1 . 2 million men under arms , including 70 infantry and 24 cavalry divisions with nearly 7 , 900 guns ( 7 , 100 field guns , 540 field howitzers , and 257 heavy guns ) . Divisions were allocated as follows : 32 infantry and 10 . 5 cavalry divisions to operate against Germany ; 46 infantry and 18 . 5 cavalry divisions to operate against Austria - Hungary ; 19 . 5 infantry and 5 . 5 cavalry divisions for the defence of the Baltic Sea and the Black Sea littorals ; and 17 infantry and 3 . 5 cavalry divisions which were to be transported in from Siberia and Turkestan . First combat ( August 1914 ) . The war in the east began with the Russian invasion of East Prussia in August 1914 and the Austro - Hungarian province of Galicia . The first effort quickly turned to a defeat following the Battle of Tannenberg in August 1914 . The second incursion was completely successful , with the Russians controlling almost all of Galicia by the end of 1914 . Under the command of Nikolai Ivanov and Aleksei Brusilov , the Russians won the Battle of Galicia in September and began the Siege of Przemyśl , the next fortress on the road towards Kraków . This early Russian success in 1914 on the Austro - Russian border was a reason for concern to the Central Powers and caused considerable German forces to be transferred to the East to take pressure off the Austrians , leading to the creation of the new German Ninth Army . At the end of 1914 , the main focus of the fighting shifted to central part of Russian Poland , west of the river Vistula . The October Battle of the Vistula River and the November Battle of Łódź brought little advancement for the Germans , but at least kept the Russians at a safe distance . The Russian and Austro - Hungarian armies continued to clash in and near the Carpathian Mountains throughout the winter of 1914 – 1915 . Przemysl fortress managed to hold out deep behind enemy lines throughout this period , with the Russians bypassing it in order to attack the Austro - Hungarian troops further to the west . They made some progress , crossing the Carpathians in February and March 1915 , but then the Germans sent relief and stopped further Russian advance . In the meantime , Przemysl was almost entirely destroyed and the Siege of Przemysl ended in a defeat for the Austrians . 1915 . In 1915 the German command decided to make its main effort on the Eastern Front , and accordingly transferred considerable forces there . To eliminate the Russian threat the Central Powers began the campaign season of 1915 with the successful Gorlice - Tarnow Offensive in Galicia in May 1915 . After the Second Battle of the Masurian Lakes , the German and Austro - Hungarian troops in the Eastern Front functioned under a unified command . The offensive soon turned into a general advance and then a strategic retreat by the Russian army . The cause of the reverses suffered by the Russian army was not so much errors in the tactical sphere , as the deficiency in technical equipment , particularly in artillery and ammunition as well as the corruption and incompetence of the Russian officers . Only by 1916 did buildup of Russian war industries increase production of war material and improve the supply situation . By mid - 1915 , the Russians had been expelled from Russian Poland and hence pushed hundreds of kilometers away from the borders of the Central Powers , removing the threat of Russian invasion of Germany or Austria - Hungary . At the end of 1915 German - Austrian advance was stopped on the line Riga – Jakobstadt – Dünaburg – Baranovichi – Pinsk – Dubno – Ternopil . The general outline of this front line did not change until the Russian collapse in 1917 . 1916 . By June 1916 there were 140 Russian infantry divisions against 105 Austro - German infantry divisions and 40 Russian cavalry divisions against 22 Austro - German . The mobilization of industry and increase of imports enabled the Russian army to resume the offensive . A large attack on the southwestern front under the leadership of General Aleksey Brusilov ( the Brusilov Offensive ) started in June . The attack , aimed against the part of the front held by Austro - Hungarians , was initially a spectacular success . The Russian army advanced to a depth of , capturing several hundred thousand prisoners and several hundred guns . The arrival of important enemy reinforcements from the west , the defeat of the Romanians , and failure of Russia ' s western allies to shake German defenses , brought the Russian advance to an end in September . On 27 August 1916 , Romania entered the war on the side of the Entente and had a successful offensive until September . After that it started to suffer great losses and several defeats from German - Austrian - Bulgarian - Ottoman forces , as the Romanian Army was poorly equipped and their Russian allies offered little support on the front . 1917 . By 1917 , the Russian economy finally neared collapse under the strain of the war effort . While the equipment of the Russian armies actually improved due to the expansion of the war industry , the food shortages in the major urban centres brought about civil unrest , which escalated into the February Revolution that forced the Tsar to abdicate . The large war casualties also created disaffection and mutinous attitudes in the army , which was fueled by Bolshevik agitators and the Russian Provisional Government ’ s new liberalization policies towards the army ( stripping officers of their mandate by giving wide sweeping powers to " soldier committees " , the abolition of the death penalty ) . The very last offensive undertaken by the Russian Army in the war was the brief and unsuccessful Kerensky Offensive in July 1917 . Throughout 1917 the German army remained largely on the defensive on the Eastern Front . The only major offensive operation was the seizure of Riga , one of the largest cities in the Russian Empire , in early September , followed by amphibious landings on Estonian islands in the course of Operation Albion during October . These operations brought German forces to within less than 500 km of the Russian capital in St . Petersburg , contributing to the chaotic political situation there . 1918 . On 7 November 1917 , the Communist Bolsheviks took power under their leader Vladimir Lenin . Lenin ’ s new Bolshevik government tried to end the war , with a ceasefire being declared on December 15 , 1917 along lines agreed in November . At the same time Bolsheviks launched a full - scale military offensive against its opponents ( separatist governments of Ukraine and Don Region ) . During the peace negotiations between Soviets and Central Powers , the Germans demanded enormous concessions , eventually resulting in the failure of the long - drawn - out peace negotiations on February 17 , 1918 . At same time the Central Powers concluded military treaty with Ukraine which was losing ground in the fight with invading Bolshevik forces . The war resumed with 52 German divisions crossing the November ceasefire line and a new offensive along the whole front . Encountering little resistance , the German army moved eastward along the Russian railways : in 124 hours they advanced 150 miles . The capital of Ukraine , Kiev , was captured on March 2 despite having been taken by the Bolsheviks only a month earlier . Treaty of Brest - Litovsk ( March 1918 ) . With the German army just from the Russian capital Petrograd ( St . Petersburg ) on March 3 , 1918 , the Treaty of Brest - Litovsk was signed and the Eastern Front ceased to be a war zone . While the treaty was practically obsolete before the end of the year , it did provide some relief to the Bolsheviks , who were embroiled in a civil war , and affirmed the independence of Ukraine . However , Estonia , Latvia , Lithuania were intended to become a United Baltic Duchy to be ruled by German princes and German nobility as fiefdoms under the German Kaiser . Finland ' s sovereignity had been declared already in December 1917 , and accepted by most nations , including France and the Soviet Union , but except the United Kingdom and the United States . The Germans were able to transfer substantial forces to the west in order to mount an offensive in France in the spring of 1918 . This offensive on the Western front failed to achieve a decisive breakthrough , and the arrival of more and more American units in Europe was sufficient to offset the German advantage . Even after the Russian collapse , about a million German soldiers remained tied up in the east until the end of the war , attempting to run a short - lived addition to the German Empire in Europe . In the end , Germany and Austria lost all their captured lands , and more , under various treaties ( such as the Treaty of Versailles ) signed after the armistice in 1918 . Casualties . The Russian casualties in the First World War are difficult to estimate , due to the poor quality of available statistics . Some official Russian sources list 775 , 400 battlefield fatalities . More recent Russian estimates give 900 , 000 battlefield deaths and 400 , 000 dead from combat wounds , or a total of 1 , 300 , 000 dead . This is about equal to the casualties suffered by France and Austria - Hungary and about one - third less than those suffered by Germany . Cornish gives a total of 2 , 006 , 000 military dead ( 700 , 000 killed in action , 970 , 000 died of wounds , 155 , 000 died of disease and 181 , 000 died while POWs ) . This measure of Russian losses is similar to that of the British Empire , 5 % of the male population in the 15 to 49 age group . He says civilian casualties were five to six hundred thousand in the first two years , and were then not kept , so a total of " over 1 , 500 , 000 " is not unlikely . He has over five million men " passing into captivity " , the majority during 1915 . When Russia withdrew from the war , 3 , 900 , 000 Russian POWs were in German and Austrian hands . This by far exceeded the total number of prisoners of war ( 1 , 300 , 000 ) lost by the armies of Britain , France and Germany combined . Only the Austro - Hungarian Army , with 2 , 200 , 000 POWs , came even close .