21 July

Events preceding British Declaration of War

 * Austria-Hungary: Conferences held at Ischl and Budapest concerning Serbia.
 * Germany: French Ambassador informs Paris of first steps towards German mobilisation.
 * Russia: Beginning of great Revolutionary Strike.

1915

 * - Ivangorod fortress invested. Russian offensive round Sokal expels enemy from right bank of Upper Bug.
 * - Italians advance at Plava (Julian).
 * - British force reach Euphrates from Kurna and captures Turkish troops. British re-occupy Sheikh Othman (Aden).