SMS Arminius [lower-alpha 1] was an ironclad warship of the Prussian Navy, later the Imperial German Navy. The ship was designed by the British Royal Navy Captain Cowper Coles and built by the Samuda Brothers shipyard in Cubitt Town, London as a speculative effort; Prussia purchased the ship during the Second Schleswig War against Denmark, though the vessel was not delivered until after the war. The ship was armed with four 21 cm (8.3 in) guns in a pair of revolving gun turrets amidships.