Design work on the "Nassau" class began in late 1903 in the context of the Anglo-German naval arms race; at the time, battleships of foreign navies had begun to carry increasingly heavy secondary batteries, including Italian and American ships with guns and British ships with guns, outclassing the previous German battleships of the with their secondaries. German designers initially considered ships equipped with secondary guns, but erroneous reports in early 1904 that the British s would be equipped with a secondary battery of guns prompted them to consider an even more powerful ship armed with an all-big-gun armament consisting of eight guns. Over the next two years, the design was refined into a larger vessel with twelve of the guns, by which time Britain had launched the all-big-gun battleship .