From gov site....
The 4th Princess Louise Dragoon Guards originated in Kingston, Ontario on 30 April 1875, when the '4th Provisional Regiment of Cavalry' was authorized to be formed. It was redesignated: '4th Regiment of Cavalry' on 7 May 1886; '4th Hussars' on 1 January 1893; and '4th Hussars of Canada' on 1 March 1932.
On 15 December 1936, it was amalgamated with the 'Princess Louise Dragoon Guards' (see below) and redesignated the '4th Princess Louise Dragoon Guards'. It was redesignated: '2nd (Reserve) Regiment, 4th Princess Louise Dragoon Guards' on 11 February 1941; '4th (Reserve) Reconnaissance Battalion, (4th Princess Louise Dragoon Guards)' on 1 April 1941; '4th (Reserve) Reconnaissance Regiment (4th Princess Louise Dragoon Guards), CAC' on 8 June 1942; '4th (Reserve) Reconnaissance Regiment (4th Princess Louise Dragoon Guards), RCAC' on 2 August 1945; '4th Armoured Car Regiment (4th Princess Louise Dragoon Guards), RCAC' on 19 June 1947; '4th Princess Louise Dragoon Guards (4th Armoured Car Regiment)' on 4 February 1949; and '4th Princess Louise Dragoon Guards' on 19 May 1958.
It was reduced to nil strength and transferred to the Supplementary Order of Battle on 12 February 1965.