The cause of World War I (also known as The Great War)= The war began with the assasination of archduke Franz Ferdinand from Austria-Hungary. This was performed by an unknown man from Serbia, and caused Germany to declare war on Serbia. Alerted by that, Britain joined the war because Serbia was their ally. A while after that, Germany threatened France ,but, Britain came to the rescue and helped. This was how the first World War began.
My World War I key vocabulary: