During World War I, a further six battalions were raised and the regiment saw action on the Western Front, the Mediterranean and the Middle East, during which its members won three Victoria Cross medals.

[5] It was one of eight Irish regiments raised largely in Ireland,[6] and served the counties of Dublin, Kildare, Wicklow and Carlow, with its garrison depot located at Naas.

They suffered heavy casualties in the process, losing, amongst others, Captain George Anderson Weldon, the first officer of the Dublins to be killed in the war.

On 30 October the garrison's commander, Sir George Stuart White VC, ordered an attack on Lombard's Kop which the Dublin Fusiliers took part in.

[12] On 15 November 1899, a detachment of Dubliners and the Durban Light Infantry were garrisoning an armoured train operating from Estcourt with the objective of monitoring Boer movements.

Among the passengers was Winston Churchill, then a war correspondent accompanying the detachment, who helped load the train engine with wounded before it made an escape attempt, pushing through the de-railed section that blocked its path and making it through safely.

[13] The Dublin Fusiliers actively took part in the efforts to lift the Siege of Ladysmith, which lasted from 30 October 1899 to 28 February 1900.

This victory led to the siege of Ladysmith being lifted the following day by cavalry, with the main force of infantry arriving on 3 March.

On 10 March 1900 Queen Victoria decreed that a sprig of shamrock be adorned on the headdress of Irish units on Saint Patrick's Day to commemorate their actions in South Africa.

This phase of the war also saw the mounted infantry companies, among which were Dublin Fusiliers MI, in their element, hunting the (now small) groups of Boers.

"[19] After the end of the Boer War the 1st Battalion transferred to Malta on the SS Dominion in November 1902,[20] and was also partly based at Crete, both in the Mediterranean.

It was posted to Egypt in 1906, where it later received its Colours at Alexandria by the regiment's Colonel-in-Chief, Prince Arthur, Duke of Connaught and Strathearn.

The regiment raised 6 battalions during the war (11 in total), serving on the Western Front, Gallipoli, Middle East and Salonika.

[21] The Division was part of the British Expeditionary Force (BEF), the professionals of the old regular army, known as the 'Old Contemptibles' after a comment made by the German Kaiser.

[25] On 24 May the battalion was subject to a German poison gas attack near Saint-Julien and effectively disintegrated as a fighting unit.

[25] The 8th and 9th Dublins, who had arrived in France in December 1915 as part of the 48th Brigade in the 16th (Irish) Division,[21] were also subject to a German gas attack at the Battle of Hulluch, near Loos, on 27 April 1916, suffering heavy casualties.

Half of the French Army, exhausted and angry at the enormous losses it had sustained, mutinied, refusing to fight unless it was to defend against German attacks.

On 21 March the regiment was on the defensive during the Battle of St. Quentin when the Germans began an immense bombardment as part of their last-gasp major offensive known as Operation Michael against British and Empire forces in the Picardy area.

[28] The 1st, 6th and 7th Dublins all took part in the Allied Gallipoli Campaign in the Dardanelles after Turkey joined the Central Powers in November 1914.

[29] In spite of the severe casualties, the British forces managed to land large numbers of troops by nightfall.

On the morning of 26 April the British force, including the Dublins, took the fortress, led by Lieutenant Colonel Doughty-Wylie, before moving onto the village of Sedd el Bahr.

On 7 June the division left the UK under the command of Irish General Bryan Mahon, arriving in Lemnos by late July in preparation for the landings at Suvla Bay, Gallipoli.

The Dublins took part in the effort to capture a position known as Chocolate Hill (7–8 August),[25] which was successfully taken, though at a heavy cost.

On 9 August the Dublins took part in the attempt to recapture Scimitar Hill,[25] and managed to gain some ground but experienced ferocious resistance from the Turks that eventually forced the British to withdraw.

[34] Meanwhile, the 6th and 7th Dublins had landed in Salonika in October 1915[21] as part of a British-French force requested by the Prime Minister of Greece, with the intention of assisting Serbia who had been invaded by Bulgaria, one of Germany's allies during the Macedonian campaign.

In October 1916 the Dublins took part in the capture of the village of Yenikoi[25] where they suffered heavy casualties, including friendly fire from their own artillery.

[38] On the night of 29 April 1916, a picket of the 5th Battalion, Royal Dublin Fusiliers stationed within the Guinness Brewery arrested and then shot dead William John Rice and Algernon Lucas.

In the court martial, it was made clear that neither Rice nor Dockeray were connected to or sympathetic to Sinn Féin or the rising.

The 2nd Dublins left war-ravaged Europe to join the Allied Army of Occupation in Constantinople, Turkey and in late 1920 moved to Multan, India, before returning to the UK in 1922.

With the outbreak of the Irish Civil War conflict some thousands of their ex-servicemen and officers chose to enlist in the Free State government's newly formed National Army.