On This Day - 21 February 1917
Theatre definitions: Western Front comprises the Franco-German-Belgian front and any military action in Great Britain, Switzerland, Scandinavia and Holland. Eastern Front comprises the German-Russian, Austro-Russian and Austro-Romanian fronts. Southern Front comprises the Austro-Italian and Balkan (including Bulgaro-Romanian) fronts, and Dardanelles. Asiatic and Egyptian Theatres comprises Egypt, Tripoli, the Sudan, Asia Minor (including Transcaucasia), Arabia, Mesopotamia, Syria, Persia, Afghanistan, Turkestan, China, India, etc. Naval and Overseas Operations comprises operations on the seas (except where carried out in combination with troops on land) and in Colonial and Overseas theatres, America, etc. Political, etc. comprises political and internal events in all countries, including Notes, speeches, diplomatic, financial, economic and domestic matters. Source: Chronology of the War (1914-18, London; copyright expired)
Germans begin to withdraw in front of Serre.
Near Jakobeny the Russians repulse a strong German attack.
At Tarvis (Trentino) Italian artillery destroy Austrian railhead.
Naval and Overseas Operations
Off Cartagena (south-east Spain) spare parts for submarines are discovered in a buoy.
French transport "Athos" sunk by a submarine in the Mediterranean.
Transport "Mendi", South African labour contingent, sunk in collision.
New British Blockade orders issued. Vessels sailing to and from neutral countries, which have access to the enemy, must put into a British port for examination, or be liable to capture.