What role did nationalism play in causing World War 1?

This was a role of nationalism as in men wanted to fight for their countries and show their loyalty. Nationalism in WW1 was mainly in the Austria-Hungary empire. They ruled over 11 different nationalities, all of whom wanted their freedom to be their own country, no more so than Serbia, who had just defeated the Turks. A serbian nationalist named Princip shot Archduke Franz Ferdinand (the heir to the throne) and his pregnant wife Sophie. This is thought to be the match that lit the dynamite for WW1.