User blog comment:Swiss Ninja/World War One Parody?/@comment-938423-20100224213908

Alliances: An alliance is an agreement made between two or more countries to give each other help if it is needed. When an alliance is signed, those countries become known as Allies.

A number of alliances had been signed by countries between the years 1879 and 1914. These were important because they meant that some countries had no option but to declare war if one of their allies. declared war first (see Important Facts above).