The 57th Batallion of Infantry was gazetted in 1867. In total, seven independent companies were amalgamated: three from Peterborough; one each from Ashburnham, Lakefield, Norwood, and Hastings. In May 1886, the companies stationed at Ashburnham, Keene, Norwood, and Hastings were moved to Peterborough, and the Battalion henceforth was viewed by the public as a city, not a country, unit. By General Order 105, 1900, the Battalion was designated as the 57th Regiment, Peterborough Rangers. In World War I, its members on Active Service took part in various C.E.F. Battalions. Upon reorganization in August 1920, the designation "Peterborough Rangers" was maintained. A more general reorganization of the militia occurred in 1936, where the 3rd Prince of Wales Canadian Dragoons, the 57th Peterborough Rangers, and 'C' Company of the 4th Canadian Machine Gun Battalion were amalgamated to form the Prince of Wales Rangers (Peterborough Regiment). In June 1940, the Regiment was authorized to mobilize `Headquarters Company' for service with the Stormont, Dundas and Glengarry Highlanders of the 3rd Division. In August 1940, men were taken for the Active Service Force. Another mobilization for active service followed in 1942. As part of this, (May 14, 1942) the 1st Battalion went to Niagara-on-the-Lake, and thence, in June 1942, to British Columbia, and to Europe in 1944 as a reinforcement Battalion. Following the end of World War II, the 2nd Battalion was deactivated, and the 1st Battalion resumed its role as a militia unit. In 1947, the Regiment ceased to exist as an infantry unit, and became part of the Royal Regiment of Canadian Artillery, being designated as the 50th Heavy Anti-Aircraft Regiment, Prince of Wales Rangers, Royal Canadian Artillery. Further adjustments and reorganization ensued. On August 22, 1955, it became the 50th Medium Anti-Aircraft Regiment (the Prince of Wales Rangers), and on June 6, 1960, was reorganized and designated as the 50th Field Artillery Regiment, Prince of Wales Rangers, Royal Canadian Artillery, being equipped with the Mm. Howitzer. On July 6, 1960, the 45th Field Battalion from Lindsay was attached to the Peterborough unit; on December 16, 1964, the 14th Field Battery was amalgamated with the unit. As of March 31, 1970, the regiment was reduced to NIL strength, and was transferred to the Supplementary order of Battle.