On 1 October 1954, two historic Canadian Militia infantry regiments ‒ The Oxford Rifles and The Canadian Fusiliers (City of London Regiment) (MG) ‒ were amalgamated to form “The London and Oxford Fusiliers (3rd Battalion, The Royal Canadian Regiment). This regiment's affiliation with The RCR was changed with a formal amalgamation on 25 April 1958 and the unit’s title became “3rd Battalion, The RCR (London and Oxford Fusiliers). In common usage, the battalion was known simply as “3rd Battalion, The Royal Canadian Regiment” by 1965, and on 22 May 1970, with the creation of a new 3rd Battalion of the regiment embodied in the Regular Force, the battalion designation evolved to its present designation as the 4th Battalion. Through the incorporation of the 4th Battalion, The RCR gained the perpetuations of both the Oxford Rifles whose origins date from 14 August 1863, as well as the Canadian Fusiliers (City of London Regiment) (MG) which originated on 27 April 1866. Both the Oxford Rifles and the Canadian Fusiliers contributed soldiers to fight in the Fenian Raids (1866-1871), the Northwest Rebellion (1885), and the South African (Boer) War (1900) (in the 2nd (Special Service) Battalion). The First World War perpetuations of Canadian Expeditionary Force units carried by these regiments, and now held by The RCR are of the 1st, 33rd, 71st, 142nd and 168th Infantry Battalions, and the 2nd Battalion, Canadian Machine Gun Corps. The regiment’s three battle honours from the War of 1812 are perpetuated from the incorporation of the Oxford Rifles and the Canadian Fusiliers’ geographical antecedents, while nine of The RCR’s First World War battle honours are the result of the regiment’s perpetuation of the 1st Battalion, CEF and the 2nd Battalion, CMGC, CEF.
Over 60 years after their amalgamation with The RCR, and more than 150 years after the creation of the amalgamated Militia regiments and over 200 years after the original geographically-perpetuated regiments fought in the War of 1812, the 4th Battalion today is a Primary Reserve infantry unit of keen, fit and knowledgeable soldiers whose members occupy positions in all walks of civil society. From policemen, firemen, nurses and lawyers to university students, industrial workers, bankers and investment brokers, the members of the 4th Battalion are, in the famous phrase attributed to SirnWinston Churchill, "twice the citizen". Since the move of the 1st Battalion to Victoria Barracks, Petawawa in 1992, the 4th Battalion has occupied the historic home of the regiment Wolseley Barracks in London, Ontario, with a detached company in Stratford, Ontario. Built in 1886-88, Wolseley Hall is a national historic site, being the first purpose-built Defence structure executed by the Dominion Government as well as being one of the first garrison sites of the Permanent Force infantry and The Royal Canadian Regiment.