The division was a voluntary 'Service' formation of Lord Kitchener's New Armies, created in Ireland from the 'National Volunteers',[1] initially in September 1914, after the outbreak of the Great War.

In December 1915, the division moved to France, joining the British Expeditionary Force (BEF), under the command of Irish Major General William Hickie, and spent the duration of the war in action on the Western Front.

Following enormous losses at the Somme, Passchendaele and Ypres, the 16th (Irish) Division required a substantial refit in England between June and August 1918, which involved the introduction of many non-Irish battalions.

Moved by the fate of Belgium, a small and Catholic country, John Redmond had called on Irishmen to enlist "in defence of the highest principles of religion and morality and right".

Wilson reported to his superior, General Sir Charles Monro (6 January) that the division, despite having been training since September–October 1914, would not be fit to serve in an active part of the line for six weeks.

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.

[8] 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.

In July 1917, during the Third Battle of Ypres, although both divisions were completely exhausted after 13 days of moving weighty equipment under heavy shelling, Gough ordered the battalions to advance through deep mud towards well fortified German positions left untouched by totally inadequate artillery preparation.

[10] The 16th Division held an exposed position from early 1918 at Ronssoy where they suffered more heavy losses during the German Army's Spring Offensive in March and being practically wiped out in the retreat which followed Operation Michael.