In the 1800's nationalism, imperialism, and militarism had a big part in the cause that started World War 1. Making territory, control, and trust an issue.
In 1871 Kaiser Wilhelm 1 sought to unite German-speaking people in Europe under Germany through the pan-German movement. Nationalism helped in enlarging Germany yet threatened the stability of other nations.
This led the Serbs wanting to create a nation of it’s own. They encouraged the Slavs to join them t