aching the foothills of the Carpathian mountains, against German and Austro-Hungarian troops of Armeegruppe von Linsingen and Armeegruppe Archduke Joseph. During the offensive the Russians inflicted c. 1,500,000 losses including c. 407,000 prisoners. Three divisions were ordered from France to the Eastern Front on 9 June and the spoiling attack on the Somme was abandoned. Only four more divisions were sent to the Somme front before the Anglo-French offensive began, bringing the total to 10 1⁄2 divisions. Falkenhayn, and then Hindenburg and Ludendorff, were forced to send divisions to Russia throughout the summer to prevent a collapse of the Austro-Hungarian army and then to conduct a counter-offensive against Romania, which declared war against the Central Powers on 27 August. In July there were 112 German divisions on the Western Front and 52 divisions in Russia and in November there were 121 divisions in the west and 76 divisions in the east.
The original British Expeditionary Force (BEF) of six divisions and the Cavalry Division, had lost most of the army's pre-war regular soldiers in the battles of 1914 and 1915. The bulk of the army was made up of volunteers of the Territorial Force and Kitchener's New Army, which had begun forming in August 1914. Rapid expansion created many vacancies for senior commands and specialist functions, which led to many appointments of retired officers and inexperienced newcomers. In 1914, Haig had been a Lieutenant-General in command of I Corps and was promoted to command the First Army in early 1915 and then the BEF in December, which eventually comprised five armies with sixty divisions. The swift increase in the size of the army reduced the average level of experience within it and created an acute equipment shortage. Many officers resorted to directive command, to avoid delegating to novice subordinates, although divisional commanders were given great latitude in training and planning for the attack of 1 July, since the heterogeneous nature of the 1916 army, made it impossible for corps and army commanders to know the capacity of each division.
Despite considerable debate among German staff officers, Falkenhayn continued the policy of unyielding defence in 1916.[Note 2] On the Somme front Falkenhayn's construction plan of January 1915 had been completed. Barbed wire obstacles had been enlarged from one belt 5–10 yards (4.6–9.1 m) wide to two, 30 yards (27 m) wide and about 15 yards (14 m) apart. Double and triple thickness wire was used and laid 3–5 feet (0.91–1.52 m) high. The front line had been increased from one trench line to three, 150–200 yards (140–180 m) apart, the first trench occupied by sentry groups, the second (Wohngraben) for the bulk of the front-trench garrison and the third trench for local reserves. The trenches were traversed and had sentry-posts in concrete recesses built into the parapet. Dugouts had been deepened from 6–9 feet (1.8–2.7 m) to 20–30 feet (6.1–9.1 m), 50 yards (46 m) apart and large enough for 25 men. An intermediate line of strongpoints (the Stützpunktlinie) about 1,000 yards (910 m) behind the front line was also built. Communication trenches ran back to the reserve line, renamed the second line, which was as well-built and wired as the first line. The second line was beyond the range of Allied field artillery, to force an attacker to stop and move field artillery forward before assaulting the line.
Anglo-French plan of attack
British intentions evolved as the military situation changed after the Chantilly Conference. French losses at Verdun reduced the contribution available for the offensive on the Somme and increased the urgency for the commencement of operations on the Somme. The principal role in the offensive devolved to the British and on 16 June, Haig defined the objectives of the offensive as the relief of pressure on the French at Verdun and the infliction of losses on the Germans. After a five-day artillery bombardment, the British Fourth Army was to capture 27,000 yards (25,000 m) of the German first line, from Montauban to Serre an