12 February

1915 (Friday)

 * Germans occupy Mariampool, Kalvaria, etc., in Poland; their centre makes progress towards Lyck (East Prussia).
 * Austrians having forced forced the Jablonitsa Pass, advance rapidly in East Galicia.
 * Raid by 34 British Naval aeroplanes on Ostend, Zeebrugge, and other points in Belgium.
 * Welsh Guards Battalion formed.