The Deccan Horse was the successor of the 1st and 2nd Cavalry Regiments of the Hyderabad Contingent. In 1903 they became the 20th Deccan Horse and the 29th Lancers (Deccan Horse) respectively. The regiments were amalgamated in 1922 to form the Royal Deccan Horse (9th Horse) which changed to The Deccan Horse (9 Horse) on Indian independence.
First World War
Regimental History: The Royal Deccan Horse In The Great War by Lieutenant-Colonel E. Tennant