On This Day - 12 April 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)
British advance north of Vimy Ridge, taking the "Pimple" and Bois en Hache, and south of Arras-Cambrai road take Heninel and Wancourt.
Asiatic and Egyptian Theatres
Turks retreat towards Deli Abbas (between Tigris and Diala).
London meetings celebrating entry of U.S.A. into war.
Spanish protest to Germany re: "San Fulgencio".
Costa Rica places territorial waters and ports at disposal of U.S.A.