Europe's great powers had been divided into two loose alliances. Germany, Austria-Hungary, and Italy formed the Triple Alliance in 1882. France, Great Britain, and Russia created the Triple Entente in 1907. In the early years of the twentieth century, a series of crises tested these alliances. This was a major cause of the war because they were willing to use war to as a way to preserve the power of their national states.

The building of the Military and Alliances