<P> The war drew in all the world 's economic great powers , assembled in two opposing alliances : the Allies ( based on the Triple Entente of the Russian Empire , the French Third Republic , and the United Kingdom of Great Britain and Ireland ) versus the Central Powers of Germany and Austria - Hungary . Although Italy was a member of the Triple Alliance alongside Germany and Austria - Hungary , it did not join the Central Powers , as Austria - Hungary had taken the offensive against the terms of the alliance . These alliances were reorganised and expanded as more nations entered the war : Italy , Japan and the United States joined the Allies , while the Ottoman Empire and Bulgaria joined the Central Powers . </P>
<P> The war drew in all the world 's economic great powers , assembled in two opposing alliances : the Allies ( based on the Triple Entente of the Russian Empire , the French Third Republic , and the United Kingdom of Great Britain and Ireland ) versus the Central Powers of Germany and Austria - Hungary . Although Italy was a member of the Triple Alliance alongside Germany and Austria - Hungary , it did not join the Central Powers , as Austria - Hungary had taken the offensive against the terms of the alliance . These alliances were reorganised and expanded as more nations entered the war : Italy , Japan and the United States joined the Allies , while the Ottoman Empire and Bulgaria joined the Central Powers . </P>
who fought against each other in world war 1
who fought against each other in world war 1
the Allies ( based on the Triple Entente of the Russian Empire , the French Third Republic , and the United Kingdom of Great Britain and Ireland ) the Central Powers of Germany and Austria - Hungary
the Allies ( based on the Triple Entente of the Russian Empire , the French Third Republic , and the United Kingdom of Great Britain and Ireland ) the Central Powers of Germany and Austria - Hungary