Balance of power in 1914

When World War I erupted in the summer of 1914, Britain, France and Russia had the demographic advantage, with a combined population of 260 million to 120 million for Austria-Hungary and Germany.
Military alliances bound Europe's great powers into rival blocs, with a Triple Alliance formed in 1882 by Germany, Austria-Hungary and Italy -- although Rome would switch sides in 1915.
The Triple Entente of London, Paris and Moscow, created in 1907, could rely on the human and material resources of vast colonial empires which spanned a quarter of the planet.
Economically, all the belligerents were dependent on one another, with Britain, France and Germany already industrialised while Austria-Hungary and Russia were still largely agrarian societies.

But the Entente powers, also known as the Allies, had access to raw materials that would become scarce in the Central Powers led by Germany and Austria-Hungary.
The French and British colonial empires doubled the population of the Triple Entente, to more than half a billion people, and the two nations were to rely during the war on some two million colonial soldiers.

At the outbreak of war, however, the size of the armed forces available to each side was much more balanced.
For military leaders who believed the war would be over within months, that relative balance of forces was a crucial consideration when the hostilities began.

Germany could mobilise around 100 divisions, or 1.8 million soldiers, along with 22 other divisions from overseas territories, to which the Habsburg Empire of Austria and Hungary added 60 more divisions, or more than a million troops.
For its part, France counted 80 divisions with 1.5 million soldiers, plus so-called territorial divisions, while Russia could attack Germany's east with around two million less well-trained soldiers.
Britain did not have military conscription, with just 170,000 mainland troops at its disposal to begin with, but its Royal Navy largely ruled the seas. Belgium contributed 100,000 soldiers, and Serbia added another 150,000.