 Marlborough was laid down at Devonport Royal Dockyard on 25 January 1912 . She was launched nearly ten months later , on 24 October , and was commissioned on 2 June 1914 . The ship was completed on 16 June 1914 , a month before the First World War broke out on the Continent . Marlborough initially joined the Home Fleets , where she served as the flagship for Sir Lewis <unk> . Following the British entry into the war in August , the Home Fleets was reorganised as the Grand Fleet , commanded by Admiral John Jellicoe . Marlborough was assigned as the flagship of the 1st Battle Squadron , where she served for the duration of the conflict . 
