The four ships in this class came about when the contracted supplier of the main armament for the Greek battleship being built in Germany was unable to supply due to the British blockade. The company – Bethlehem Steel in the United States – instead offered to sell the four twin gun turrets to the Royal Navy on 3 November 1914. The Royal Navy was using obsolete pre-dreadnought battleships for shore bombardment in support of the army in Belgium, and a design for a shallow-draught warship (known as "Monitors") suitable for shore-bombardment was quickly designed and built to use these turrets. The ships were laid down and launched within six months.