Developed from the Covenanter, The Crusader III saw service between 1941 and 1943 mostly in the North African campaign. By the middle of the war, as Crusaders were being replaced by M4 Shermans, the British converted some by fitting 40mm Bofors (Mk I & Mk III) and later twin 20mm Oerlikon anti aircraft guns (Mk II and Mk III). These AA tanks saw service, albeit limited because of Allied air superiority, during the NW European campaign of 1944-1945.