Seventeen Cavalry Reserve Regiments were formed by the

British Army The British Army is the principal land warfare force of the United Kingdom, a part of the British Armed Forces along with the Royal Navy and the Royal Air Force. , the British Army comprises 79,380 regular full-time personnel, 4,090 Gurkha ...

on the outbreak of the

Great War World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

in August, 1914. These were affiliated with one or more active

cavalry regiments Historically, cavalry (from the French word ''cavalerie'', itself derived from "cheval" meaning "horse") are soldiers or warriors who fight mounted on horseback. Cavalry were the most mobile of the combat arms, operating as light cavalry in ...

, their purpose being to train replacement drafts for the active regiments. In 1915, the 3rd Line regiments of the

Yeomanry Yeomanry is a designation used by a number of units or sub-units of the British Army Reserve, descended from volunteer cavalry regiments. Today, Yeomanry units serve in a variety of different military roles. History Origins In the 1790s, f ...

were also affiliated with the Cavalry Reserve and, in September 1916, the Household Cavalry Reserve Regiment was formed in Windsor, supplying replacements to the dismounted

Household Battalion The Household Battalion was an infantry battalion of the British army during the Great War. It was formed in September 1916 from the reserves of the Household Cavalry regiments (the 1st Life Guards, 2nd Life Guards and the Royal Horse Guards) to ...

. In 1917, the regiments underwent major reorganization, being reduced to ten in number. Although nominally cavalry, many of the drafts ended up being converted into infantry in order to satisfy the manpower demands of trench warfare. Despite being training and not combat formations, several were involved in the putting down of the

Easter Rising The Easter Rising ( ga, Éirí Amach na Cásca), also known as the Easter Rebellion, was an armed insurrection in Ireland during Easter Week in April 1916. The Rising was launched by Irish republicans against British rule in Ireland with t ...

in Dublin in April 1916. A little after noon on Easter Monday, a mixed troop of 9th and

12th Lancers The 12th (Prince of Wales's) Royal Lancers was a cavalry regiment of the British Army first formed in 1715. It saw service for three centuries, including the First World War and the Second World War. The regiment survived the immediate post-war ...

, attached to the 6th Cavalry Reserve Regiment at Marlborough Barracks in

Phoenix Park The Phoenix Park ( ga, Páirc an Fhionnuisce) is a large urban park in Dublin, Ireland, lying west of the city centre, north of the River Liffey. Its perimeter wall encloses of recreational space. It includes large areas of grassland and t ...

, was dispatched to investigate a "disturbance" at

Dublin Castle Dublin Castle ( ga, Caisleán Bhaile Átha Cliath) is a former Motte-and-bailey castle and current Irish government complex and conference centre. It was chosen for its position at the highest point of central Dublin. Until 1922 it was the s ...

. As they cantered down Sackville Street, they were fired upon by rebels who had taken up positions in and on the roof of the

General Post Office The General Post Office (GPO) was the state postal system and telecommunications carrier of the United Kingdom until 1969. Before the Acts of Union 1707, it was the postal system of the Kingdom of England, established by Charles II in 1660. ...

. Three troopers were killed instantly and one was mortally wounded, becoming the first military casualties of the rising. The same evening, 1,600 men of the 3rd Reserve Cavalry Brigade (consisting of the 8th, 9th and 10th Cavalry Reserve Regiments) arrived from their barracks at

the Curragh The Curragh ( ; ga, An Currach ) is a flat open plain of almost of common land in County Kildare. This area is well known for Irish horse breeding and training. The Irish National Stud is located on the edge of Kildare town, beside the ...

to support the local Dublin garrison. General J.G. Maxwell, ''From the General Officer, Commanding-in-Chief, The Forces in Ireland. To the Field-Marshal, Commanding-in-Chief, The Home Forces.'' 25 May 1916

Original August 1914 Formations

Formed in 1916

After 1917 re-organization

Notes

References

Bibliography