Jellicoe, Sir John (1859-1935) Commander-in-chief of the Grand Fleet from August 1914 until November 1916, when he was replaced by David Beatty. Jellicoe was criticised in some quarters for his cautious tactics at the Battle of Jutland (31 May-1 June 1916). He subsequently served as first sea lord until December 1917.

July crisis Term used by historians to describe the period of escalating diplomatic and military tensions in Europe during the summer of 1914. It began with the assassination of Archduke Franz Ferdinand on 28 June and ended with the beginning of the First World War on 1 August.

Jutland Peninsula extending into the North Sea, of which the northern part is owned by Denmark and the southern part by Germany. The only set-piece naval battle of the First World War - between the British Grand Fleet and the German High Seas Fleet - was fought 75 miles off the Jutland coast. Widely considered to have ended in a 'draw', a result that kept Britain in control of the seas.