The 16th Irish Division rose to prominence on 3 September 1916 with battles in Guillemont and Ginchy. It consisted of a range of units, including the Royal Irish Rifles, Connaught Rangers, Dublin Fusiliers and Munster Fusiliers. About 4,300 men from the division were killed or wounded in the clashes, which lead to the successful capture of the two villages from German soldiers.
The Battle of Guillemont (3–6 September 1916) was an attack, during the Battle of the Somme in the First World War, by the British Fourth Army against the German 2nd Army near the village of Guillemont in northern France. The village is on the D 20 running east to Combles and the D 64 south-west to Montauban. Longueval and Delville Wood lie to the north-west and Ginchy to the north-east. The village was on the right flank of the British sector, near the boundary with the French Sixth Army. The Fourth Army had advanced close to Guillemont during the Battle of Bazentin Ridge (14–17 July) and the capture of the village was the culmination of British attacks which began on the night of 22/23 July. The attacks were intended to advance the right flank of the Fourth Army and eliminate a salient further north at Delville Wood. German defences ringed the wood and had observation over the French Sixth Army area to the south, towards the Somme river.
The 16th Division played an important part in capturing the towns of Guillemont and Ginchy, although they suffered massive casualties. During these successful actions between 1 and 10 September casualties amounted to 224 officers and 4,090 men; despite these very heavy losses the division gained a reputation as first-class shock troops. Out of a total of 10,845 men, it had lost 3,491 on the Loos sector between January and the end of May 1916, including heavy casualties from bombardment and a gas attack at Hullach in April. Bloodletting of this order was fatal to the division's character, for it had to be made good by drafts from England.