Armed forces

The armies, fleets and air services that fought this war.

When they were formed, who commanded them, where they fought and what became of them. Below the text, their battles and every event of the chronicle connected with them.

• United KingdomBritish Expeditionary ForceThe British army in France and Belgium: from a few divisions of regulars at Mons in 1914 to five armies that broke the Hindenburg Line in 1918.
• Czechoslovak LegionCzechs and Slovaks on the Allied side. In Russia their army grew into a corps, in 1918 it seized the Trans-Siberian Railway, and it went home in 1920.
• RussiaEighth ArmyBrusilov's army: in 1914 it conquered Galicia and reached the Carpathians, in June 1916 under Kaledin it took Lutsk, and in July 1917 Kornilov led it to Kałusz.
• GermanyEleventh ArmyAn army of Imperial Germany that broke the Russian front at Gorlice in 1915 and conquered Serbia, and until 1918 held the Macedonian front.
• RussiaEleventh ArmyThe army that took Przemyśl in March 1915 and Brody in 1916, broke the front at Zborów in July 1917 and fell apart near Tarnopol.
• GermanyFourth ArmyImperial German army that beat the French in the Ardennes, then from autumn 1914 to the end of the war fought in Flanders, at Ypres, Passchendaele and Kemmel.
• United KingdomGrand FleetThe Royal Navy's main battle fleet, 1914–1919. From Scapa Flow it held the High Seas Fleet in check, fought at Jutland and took the German fleet's surrender.
• United KingdomGurkhasNepalese soldiers of the Gurkha Rifles regiments of the Indian Army. They fought in Flanders, at Gallipoli, in Mesopotamia, Persia and Palestine.
• GermanyHigh Seas FleetImperial Germany's main battle fleet. It fought the Grand Fleet at Jutland, then stayed in port, mutinied in 1918 and went down at Scapa Flow in 1919.
• GermanyNinth ArmyAn army of Imperial Germany that fought at Warsaw and Łódź, took Warsaw in 1915 and Bucharest in 1916, and in 1918 fought on the defensive at Soissons.
• PortugalPortuguese Expeditionary CorpsPortugal's corps on the Western Front: from 1917 it held a sector in Flanders, and on 9 April 1918 a German attack on the Lys shattered it.
• United KingdomRoyal Air ForceAn independent air force formed on 1 April 1918 from the RFC and the RNAS. Until the end of the war it fought on every British front and bombed Germany.
• United KingdomRoyal Flying CorpsThe British Army's air arm: reconnaissance at Mons and the Marne, the fight for the sky over the Western Front, home defence. In April 1918 it joined the RAF.
• United KingdomRoyal Naval Air ServiceThe Royal Navy's air arm, 1914–1918: raids on Zeppelin bases, seaplanes over the Dardanelles, flying boats against U-boats. In 1918 it joined the RAF.
• United KingdomRoyal NavyBritain's navy, 1914–1918: the blockade of Germany, the Dardanelles, Jutland and the U-boat war. Convoys saved shipping, and the German fleet surrendered.
• GermanySouth ArmyA German and Austro-Hungarian army that fought in the Carpathians and on the Stryj in 1915, then held the front in Eastern Galicia until 1918.
• RussiaThird ArmyThe army of Ruzsky and Radko Dimitriev: in 1914 it took Lviv and besieged Przemyśl, in May 1915 it took the main blow of the Central Powers at Gorlice.