the defenders who took refuge in the tower of David
the conflict at the temple of Solomon
World war 1 broke out in 1914 because a group of Serbian nationalists (The Black Hand) assassinated the duke of Austria-Hungary. Austria -Hungary threatened Serbia with a bunch of wishes that they wanted Serbia to due for them. Due to the treaty between Serbia and Russia, Serbia said no. Germany, who had a treaty with Austria-Hungary threatened to attack if Russia mobilized its army. Russia did and Germany invaded Belgium. This brought Great Britain and France into the war.
A feeling of strong devotion to one's country is called : nationalism
People with nationalism principle tend to be capable to do anything in order to bring benefit to their country, such as waging war, conquering more territory for the country, etc
hope this helps
The renaissance made a big deal