The 12th Mounted Rifles was formed 17 March 1911. During World War I

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

 they formed part of the Otago Mounted Rifle Regiment

Otago Mounted Rifle Regiment

The Otago Mounted Rifle Regiment was a New Zealand Mounted Regiment formed for service during the Great War. It was formed from units of the Territorial Force consisting of the 5th Mounted Rifles the 7th Mounted Rifles and the 12th Mounted Rifles.They saw service during the Battle of Gallipoli,...

 and saw service during the Battle of Gallipoli

Battle of Gallipoli

The Gallipoli Campaign, also known as the Dardanelles Campaign or the Battle of Gallipoli, took place at the peninsula of Gallipoli in the Ottoman Empire between 25 April 1915 and 9 January 1916, during the First World War...

, afterwards they were withdrawn to Egypt

Egypt

Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...

 and later were the only New Zealand Mounted troops to serve in France

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 with the New Zealand Division

New Zealand Division

The New Zealand Division was a World War I infantry division formed in Egypt in January 1916 following the evacuation of Gallipoli. At the outbreak of war the New Zealand Expeditionary Force contained a single infantry brigade which was combined with the unattached Australian 4th Infantry Brigade...

.

Great War Battles

• Battle of Gallipoli
  Battle of Gallipoli
  The Gallipoli Campaign, also known as the Dardanelles Campaign or the Battle of Gallipoli, took place at the peninsula of Gallipoli in the Ottoman Empire between 25 April 1915 and 9 January 1916, during the First World War...
  
  
• Battle of Flers - Courcelette. 15 - 22 Sep 1916.
• Battle of Morval
  Battle of Morval
  The Battle of Morval, which began on 25 September 1916, was an attack by the British Fourth Army on the German-held villages of Morval, Gueudecourt and Lesboeufs during the Battle of the Somme. These villages were originally objectives of the major British offensive of 15 September, the Battle of...
  
  . 25 - 28 Sep 1916.
• Battle of Le Transloy
  Battle of Le Transloy
  The Battle of Le Transloy was the final offensive mounted by the British Fourth Army during the 1916 Battle of the Somme.-Prelude:With the successful conclusion of the preceding Battle of Morval at the end of September, the Fourth Army of Lieutenant General Henry Rawlinson had finally captured the...
  
  . 1 - 18 Oct 1916.
• Battle of Messines
  Battle of Messines
  The Battle of Messines was a battle of the Western front of the First World War. It began on 7 June 1917 when the British Second Army under the command of General Herbert Plumer launched an offensive near the village of Mesen in West Flanders, Belgium...
  
  . 7 - 14 Jun 1917.
• Battle of Polygon Wood
  Battle of Polygon Wood
  The Battle of Polygon Wood took place during the second phase of the Battle of Passchendaele in World War I. The battle was fought near Ypres, Belgium, in an area named the Polygon Wood after the layout of the area...
  
  . 26 Sep - 3 Oct 1917.
• Battle of Broodseinde
  Battle of Broodseinde
  The Battle of Broodseinde was the most successful attack of the Battle of Passchendaele. Using the "bite and hold" tactic , the Allied forces conducted an attack on well-entrenched German forces and showed that it was possible for the allies to overcome even the stoutest German...
  
  . 4 Oct 1917.
• Battle of Passchendaele. 12 Oct 1917.
• Battle of Arras. 28 Mar 1918.
• Battle of the Ancre
  Battle of the Ancre
  The Battle of the Ancre was the final act of the 1916 Battle of the Somme. Launched on 13 November 1916 by the British Fifth Army of Lieutenant General Hubert Gough, the objective of the battle was as much political as military.-Prelude:The Allied commanders were due to meet at Chantilly on 15...
  
  . 5 Apr 1918.
• Battle of Albert
  Battle of Albert (1918)
  Battle of Albert was the third battle by that name fought during World War I, following the First Battle of Albert, and the Second Battle of Albert, with each of the series of three being fought roughly two years apart...
  
  . 21 - 23 Aug 1918.
• Battle of Bapaume
  Battle of Bapaume
  Battle of Bapaume may refer to:*Battle of Bapaume , a battle of the Franco-Prussian War*First Battle of Bapaume, a battle during the German Spring Offensive of World War I...
  
  . 31 Aug - 3 Sep 1918.
• Battle of Havrincourt
  Battle of Havrincourt
  - Notes :# - a mistake on the part either of Byng or of Repington, as it was actually the 62nd Division....
  
  . 12 Sep 1918.
• Battle of the Canal du Nord
  Battle of the Canal du Nord
  The Battle of Canal du Nord was part of a general Allied offensive against German positions on the Western Front during the Hundred Days Offensive of World War I. The battle took place in the Nord-Pas-de-Calais region of France, along an incomplete portion of the Canal du Nord and on the outskirts...
  
  . 27 Sep - 1 Oct 1918.
• Battle of Cambrai
  Battle of Cambrai (1918)
  The Battle of Cambrai was a battle between troops of the British First, Third and Fourth Armies and German Empire forces during the Hundred Days Offensive of the First World War. The battle took place in and around the French city of Cambrai, between 8 and 10 October 1918...
  
  . 8 - 9 Oct 1918.
• Pursuit to the Selle
  Pursuit to the Selle
  The Pursuit to the Selle, a portion of which is referred to as the Battle of the Selle, was a series of skirmishes between allied forces and the German Army, fought during what is known as The Last Hundred Days of World War I, and which occurred after the Second Battle of Cambrai.The pursuit began...
  
  . 9 - 12 Oct 1918.
• Battle of the Selle. 17 - 25 Oct 1918.
• Battle of the Sambre
  Battle of the Sambre
  The Battle of the Sambre refers to two battles fought along the Sambre River during World War I:* Battle of the Sambre , commonly known as the Battle of Charleroi* Battle of the Sambre - the final British offensive of the war...
  
  . 4 Nov 1918, including the Capture of Le Quesnoy.

Between the wars

They amalgamated with the 5th Mounted Rifles (Otago Hussars)

5th Mounted Rifles (Otago Hussars)

The 5th Mounted Rifles was formed on March 17, 1911. It formed part of the Otago Mounted Rifle Regiment so they saw service during the Battle of Gallipoli, Egypt. They later served in France with the New Zealand Division and were the only New Zealand Mounted troops to serve in France.-Great War...

 and the 7th (Southland) Mounted Rifles

7th (Southland) Mounted Rifles

The 7th Mounted Rifles was raised on 17 March 1911. During World War I they formed part of the Otago Mounted Rifle Regiment and served in the Battle of Gallipoli and was then withdrawn to Egypt . They would later serve in France,with the New Zealand Division.-Great War Battles:*Battle of...

 to become the 5th New Zealand Mounted Rifles in 1921.