Italy had been part of the Triple Alliance since 1882, but were initially not involved in WW1. They decided to stay neutral since Austria had declared war on Serbia without informing Italy, hence had broken the terms of the alliance. However, the Liberals in power believed that because of their territorial ambitions in Europe, the best solution was to see which side would give Italy the best terms for joining the war. After having negotiated with the Triple Alliance in 1914-15, Italy's government realized that their ambitions would not be met in an alliance with Austria, hence decided to join the Triple Entente (consisting of France, Russia and Britain), who would meet their wishes. Thus, they signed the Treaty of London, promising to fight on the side of the Triple Entente.