Maurice FitzGerald, 6th Duke of Leinster (1 March 1887 – 4 February 1922), was the eldest son of the 5th Duke of Leinster and his wife, the former Lady Hermione Wilhelmina Duncombe, a daughter of the 1st Earl of Feversham. Born at Kilkea Castle and never married but was educated at Eton College, he acceded to the dukedom and its related titles upon his father's death from typhoid fever in 1893, at age 42; his mother died of tuberculosis in 1895, at age 30. The Duke had three siblings: A sister (born 1885 – died 5 February 1886), Lord Desmond FitzGerald (1888–1916), Edward FitzGerald, 7th Duke of Leinster (1892–1976), whose biological father it has been alleged was the 11th Earl of Wemyss. During his minority, his family's large estates in County Kildare were sold in November 1903 by his trustees to 506 tenant farmers via the Land Commission. Some of the lands had a title dating back to the Norman invasion of Ireland in 1171. The 45,000 acres sold for £766,000, a huge amount at the time, but this had to cover costs, some mortgages and £272,000 that was earmarked to family trusts for the surviving younger children of the 4th duke.

The 5th Royal Irish Lancers was a cavalry regiment of the British Army. It saw service for three centuries. The regiment was originally formed in 1689 by Brigadier James Wynne as James Wynne's Regiment of Dragoons. It fought at the Battle of the Boyne in July 1690 and at the Battle of Aughrim later that month under King William III. Renamed the Royal Dragoons of Ireland in 1704, it went on to fight under the Duke of Marlborough at the Battle of Blenheim in August 1704 during the War of the Spanish Succession. At the Battle of Ramillies in May 1706 the regiment helped capture the entire French "Regiment du Roi", after which it fought at the Battle of Oudenarde in July 1708 and at the Battle of Malplaquet in September 1709. In 1751, it was retitled 5th Regiment of Dragoons and in 1756 it became the 5th (or Royal Irish) Regiment of Dragoons. As such, it served in Ireland and had the honour of leading the charge against the rebels at the Battle of Enniscorthy in May 1798 during the Irish Rebellion of 1798. However, its troops were accused of treachery: their accusers claimed their ranks had been infiltrated by rebels. Following an investigation, it was found that a single individual, James M'Nassar, had infiltrated the regiment: he was ordered to be "transported beyond the seas". According to Continental Magazine: The circumstance was commemorated in a curious way. It was ordered that the 5th Royal Irish Light Dragoons should be erased from the records of the army list, in which a blank between the 4th and 6th Dragoons should remain forever, as a 

memorial of disgrace. For upward of half a century this gap remained in the army list, as anybody may see by referring to any number of that publication of half-a-dozen years back. The regiment was reformed in 1858, keeping its old number and title, but losing precedence, being ranked after the 17th Lancers. It was immediately converted into a lancer regiment and titled 5th (or Royal Irish) Regiment of Dragoons (Lancers). In 1861, it was renamed the 5th (or Royal Irish) Lancers and then the 5th (Royal Irish) Lancers. The regiment served in India between November 1863 and December 1874 and a contingent joined the Nile Expedition in autumn 1884. It then fought against the forces of Osman Digna near Suakin in 1885 during the Mahdist War. The regiment again left for India in November 1888, serving there for ten years until they were posted to South Africa in February 1898. They were stationed at Ladysmith until October 1898, when they went to Pietermaritzburg, where they remained until the outbreak of the Second Boer War in October 1899.As one of two cavalry regiments stationed in South Africa on the outbreak of war, the regiment consequently took part in the early fighting. They fought at the Battle of Elandslaagte on 21 October 1899, at the Battle of Rietfontein on 24 October 1899, and was part of the besieged garrison of Ladysmith during the Siege of Ladysmith November 1899 to February 1900. After the relief of that town, they were re-horsed, and formed part of General Sir Redvers Buller′s army, taking part in all his actions until his Natal army joined with the main army at Belfast. They accompanied Buller in his advance into the Lydenburg district, and then, under General John Brocklehurst, made the forced march through the Dulstroom Valley to join General Ian Hamilton. Later they formed part of General Smith-Dorrien′s flying column. In January 1901, still under General Smith-Dorrien, they covered the left of General Sir John French′s big movement down to the Swaziland border. They then served under General Sir Bindon Blood, and operated in the Carolina district until July 1901, when they travelled by rail to Cape Colony. Here they formed part of Colonel Hunter-Weston′s mobile column. The regiment thus stayed in South Africa throughout the hostilities, which ended with the Peace of Vereeniging on 31 May 1902. Following the end of the war, 340 officers and men of the regiment left South Africa on the SS City of Vienna, which arrived at Southampton in October 1902.