THE IMMEDIATE CAUSE OF WORLD WAR I THAT MADE THE AFOREMENTIONED ITEMS COME INTO PLAY (ALLIANCES, IMPERIALISM, MILITARISM, NATIONALISM) WAS THE ASSASSINATION OF ARCHDUKE FRANZ FERDINAND OF AUSTRIA-HUNGARY. ... WHEN RUSSIA BEGAN TO MOBILIZE DUE TO ITS ALLIANCE WITH SERBIA, GERMANY DECLARED WAR ON RUSSIA. HE DIED FROM AIRSTRIKE AND WAR IS UPON US