World War I (1914 – 1918), also known as the First World War or the Great War, was an armed military conflict initially between several European nations and their colonial empires, which soon expanded to include a number of countries from across the globe.
Principally, the conflict was fought between the two major alliances; the Triple Entente, comprising the United Kingdom, France, and Russia, and the Triple Alliance of Germany and Austria-Hungary. Although Italy had also been a member of the Triple Alliance, it did not join the Central Powers, as Austria-Hungary had taken the offensive against the terms of the alliance.
The war began after the assassination of the Austro-Hungarian heir presumptive Franz Ferdinand by the Serb nationalist group, the Black Hand. The death of Franz Ferdinand led to tensions between the European nations, leading to war.
This conflict, like so many before and after it, was heavily influenced by the ongoing Assassin-Templar War, with members of each Order fighting on either side. Notably, during the Christmas truce of 1914, a Templar named Erich Albert, a general in the German Army, was assassinated by an unnamed British Assassin just moments after the two had worked together to save a wounded soldier's life.
The war also affected London, with Zeppelin raids bringing destruction to the city throughout the conflict. In 1916, at the behest of Winston Churchill, the Assassin Lydia Frye eliminated a German spy ring operating around Tower Bridge. The spy ring was led by a Templar Master Spy, who eventually fell to Lydia's blade.