 Germany now felt threatened by Russia and responded with her own mobilisation and declaration of war on 1 August 1914.At the opening of hostilities, the Russians took the offensive against both Germany and Austria-Hungary.Between 1873-1887, Russia was allied with Germany and Austria-Hungary in the League of the Three Emperors, then with Germany in the 1887-1890 Reinsurance Treaty; both collapsed due to the competing interests of Austria and Russia in the Balkans.