Only when Belgium—a small nation that was in a sense under the guardianship of Great Britain, so far as its nationality and neutrality were concerned—was invaded by Germany without warning, did Britain feel it incumbent upon her to come to its aid. This may not have been entirely an act of benevolence. There was a probability that Germany, once in control of Belgium, could not readily let go. She might add it to her empire, a fact likely to seriously affect British sea-power. However this be, Great Britain lost no time after the invasion in becoming a party to the continental war, sending her fleet abroad and enlisting troops for service in the aid of her allies, France and Belgium. Italy, a member of the Triple Alliance, the other members of which were Germany and Austria, was the only one of the great Powers that held aloof. She had absolutely nothing to gain by taking part in the war, while her late large expenses in the conquest of Tripoli had seriously depleted her war chest. As regards her alliance with Germany and Austria, it put her under no obligation to come to their aid in an offensive war. Her obligation was restricted to aid in case they were attacked, and she justly held that no such condition existed. As a result, Germany and Austria found themselves at war with the three powerful members of the Triple Entente, while Italy, the third member of the Triple Alliance, declined to draw the sword. The defection of Italy was a serious loss to the power of the allies, so much so that Emperor William threatened her with war if she failed to fulfil her assumed obligations. This threat Italy quietly ignored. She gave indications, in fact, that her sympathies were with the opposite party. Thus Germany and Austria found themselves pitted against three great Powers and a possible fourth, with the addition of the two small nations of Servia and Belgium. And the latter were not to be despised as of negligible importance. Servia quickly showed an ability to check the forward movements of Austria, while Belgium, without aid, long held a powerful German army at bay, defending the city and fortresses of Liege with a boldness and success that called forth the admiring acclamations of the world. THE TRIPLE ALLIANCE AND TRIPLE ENTENTE