The Triple Entente and Triple Alliance networks were set before the war. Also, the Little Entente and the Balkan Pact lost their importance. The underlying reason for the decision was a secret pact between The Entente and Romania. The Allies, known initially as "The Triple Entente", comprised the British Empire, France and Russia. In September the Entente and their Greek allies attacked in Macedonia. The interventionists sought to use the Triple Entente to contain German expansion. The inevitable consequence of the successful performance of the Little Entente was its institutionalisation. Russia and the Triple Entente declared war on the Ottoman Empire. The successful performance of the Little Entente resulted in its institutionalisation. It finally ended with an Anglo-Russian Entente in 1907. The Triple Entente powers were highly supportive. The Eastern front of the Allied (Entente) Powers completely collapsed. The Czechoslovak Legion fought on the side of the Entente. The agreement led to the formation of the Triple Entente. With the formation of the Triple Entente, Germany began to feel encircled.