The Central Powers faced and was defeated by the Allied Powers that had formed around the Triple Entente. The Powers' origin was the alliance of Germany and Austria-Hungary in 1879. Despite having nominally joined the Triple Alliance before, Italy did not take part in World War I on the side of the Central Powers; the Ottoman Empire and Bulgaria did not join until after World War I had begun, even though the Ottoman Empire had retained close relations with both Germany and Austria-Hungary since the beginning of the 20th century.