Although the Balkan crisis differed little from those that had preceded it, Austria–Hungary was determined to use it to permanently crush the Serbian threat. ‘The Coming of War’ investigates the decision-making process that led each state to war, as well as their military situations in 1914 following the pre-war arms race. After securing German support in the event of war, the Austrian government issued Serbia with an impossible ultimatum. As expected, the Serbians refused, forcing the Russians to mobilize in their defence. German mobilization came just days later, their invasion of Belgium provoking Britain to declare war.