Before the war, European countries had formed alliances with each other to protect themselves. However, by doing this they had divided themselves into two groups. When Archduke Franz Ferdinand of Austria was assassinated on 28 June 1914, Austria-Hungary blamed Serbia and declared war on them. Serbia's ally Russia then declared war on Austria-Hungary. This set off a chain of events in which the two groups of countries declared war on each other. The two sides were the Allied Powers (mainly Russia, France and the British Empire) and the Central Powers (mainly Germany, Austria-Hungary and the Ottoman Empire).