It formed part of the German defensive system in the Somme sector of the Western Front during the First World War and consisting of a mass of machine-gun emplacements, trenches and dug-outs.

[4] On the Western Front, General Erich Falkenhayn Chief of the General Staff at the Oberste Heeresleitung (OHL, German army high command) instituted a construction plan in January 1915, by which the western armies would create field fortifications built to a common system, intended to economise on infantry, while offensive operations were conducted on the Eastern Front.

The second position was built beyond the range of opposing field artillery, to force an attacker to stop and move guns and ammunition forward before assaulting the line.

[5] Behind the German front line, the ground rose steeply to the west for 1,000 yd (910 m), to the top of Thiepval ridge, 250 ft (76 m) higher than the Ancre valley.

[10] At the end of July 1915, fresh troops were observed moving into the French positions north of the Somme, opposite Reserve Infantry Regiment 99 (RIR 99) and on 1 August, were identified at Thiepval Wood as British soldiers ("dressed in brown suits").

In the X Corps section allocated to the 36th (Ulster) Division (Major-General Oliver Nugent), ten Russian saps were dug from the British lines into no-man's land, north-east of Thiepval Wood; each of the tunnels housed two mortars.

[18] At 7:15 a.m., four hours after dawn, the Irish troops formed up in no man's land, most along the sunken Thiepval–Hamel road, obscured by the bombardment and smoke screens on the flanks and moved to within 150 yd (140 m) of the German front trench.

The left hand battalion of RIR 99 had repulsed the attack on Thiepval but the centre and right, from the village to the Ancre south of St Pierre Divion, had been broken through, most of the troops having been trapped underground and taken prisoner.

As soon as the British bombardment lifted, the only reserves nearby, the recruit battalion of IR 180 and a machine-gun company, occupied the Grandcourt Line around Thiepval.

[20] The 107th Brigade advanced to the A Line but the 10th Royal Irish Rifles on the right, had to pass through machine-gun fire from front, right flank and right rear, which caused many casualties.

The brigade advanced for about 1,000 yd (910 m) in a "wild and desperate venture", before the survivors were repulsed from the objective by German troops in the D Line (Grandcourt Trench).

[21] An attack from the east face of Schwaben Redoubt was met by machine-gun fire but a party of about fifty men reached an artillery position in a fold known as Artilleriemulde (Boom Ravine), in front of the Grandcourt Line.

Auwäter ordered the counter-attack to begin immediately by three groups, from the north-east, east and south-east, to forestall a wheeling movement against Thiepval and Ovillers.

In the centre, the counter-attack began from Staufen-Feste (Stuff Redoubt), with three companies of BRIR 8 but was promptly engaged by British artillery and forced under cover.

The advance was continued along Hessen Weg, which led from Courcelette to Thepval and then moved into the open opposite the south-eastern corner of Schwaben Redoubt.

By midnight the ridge had been re-occupied and two more battalions of IR 180 had arrived and moved to the Hansalinie and the redoubt, available to reinforce the front line from Thiepval to the Ancre.

[26] The Reserve Army kept up a continuous bombardment on the Thiepval–St Pierre Divion area after 1 July, which reduced the German field defences to wreckage and the defenders dispersed among shell-holes and the surviving dug-outs.

[27] On 3 September, the British attacked along the Ancre river despite poor weather, to gain strictly limited objectives in the Anzac and II Corps sectors, east of Thiepval.

The infantry attack began at 5:13 a.m., from the Hamel–Thiepval road behind a creeping barrage, as the heavy artillery bombarded positions to the south-east, Schwaben Redoubt and the Strasburg Line.

Direction was lost and one battalion missed the Pope's Nose salient; isolated groups of Germans held out in parts the front line.

[28] The 146th Brigade on the left, was caught by machine-gun fire from the Pope's Nose and the right-hand battalion failed to reach the German front trench.

Visual signalling failed in the mist and few runners got through the German standing barrage, which left the situation at the front unclear, until stragglers began to appear.

[31] On 28 September, the 53rd Brigade formed up for the attack, on tapes facing north-west from Zollern Trench, the left-hand battalion to capture the redoubt.

Poor weather restricted flying on 29 September but the next day was bright and low-flying sorties discovered that most of the Schwaben Redoubt had been captured.

[33] The 55th Brigade in the Schwaben Redoubt, was attacked by II Battalion, IR 66 at 5:15 a.m. on 2 October, which gained a small area after a bombing fight had lasted all day.

[34] On 14 October, the 4th/5th Black Watch, the 1st Cambridge and the 17th King's Royal Rifle Corps of the 117th Brigade, attacked the north side of the redoubt.

Front line trenches had been demolished, barbed wire had been swept aside and dug outs caved in, which caused the 9th Company of III battalion, RIR 99 many casualties.

Communications on the German side broke down but news of the breakthrough reached Soden quickly, from Beaucourt Redoubt on the north bank of the Ancre.

[38] Artillery support for the 3 September attack was excellent but lack of surprise and the dominating position of Schwaben Redoubt made success unlikely.

At the beginning of the fight nearly all of the officers of the attacking companies were either killed or wounded, and it says much for the grit and endurance of the men that the 4/5th never wavered; it carried its attack forward with great gallantry and determination, hung on for hours under heavy German shell fire, repelled all enemy counter-attacks and, finally, having consolidated the captured position, handed it over intact to the relieving platoons of A Company.On 1 July, the 36th (Ulster) Division suffered 5,104 casualties and the 49th (West Riding) Division suffered 590.