This revolver was manufactured in the Colt London factory in 1855 and was used to arm the Canadian militia. In the mid-1850s, Canada was bolstering its militia forces due to United Kingdom's involvement in the Crimean War which had dramatically reduced the number of soldiers stationed within Canada, but the force was still fairly small at 5,000 active volunteers. It has the "-ADDRESS. COL. COLT. LONDON-" barrel address, London proof marks on the barrel and cylinder, "COLT'S/PATENT" on the left side of the frame, standard Naval cylinder scene, and upside down "U.C/A/20" letters on the left side of the grip which indicates this revolver was issued to the Upper Canada Militia, Troop A, man number 20. Matching serial numbers on barrel, trigger guard, back strap, cylinder, loading lever, wedge, and arbor pin.