It further appears that, in 1873, Bolivia and Peru had entered into a secret alliance, by the terms of which each was to protect the others independence and territorial integrity from foreign aggression, and that in 1874 another treaty between Chile and Bolivia was negotiated, having in view the settlement of certain differences, but which the Bolivian Congress had refused to ratify except on condition that an export duty on nitrates should thereafter be paid. Chile remonstrated, contending that such a tax would be in violation of the treaty of 1866. Bolivia, it was charged, sought to impose it nevertheless and seized the property of the Chileno-British company on default in payment. The situation having thus become acute, Chile sent a fleet to protect the interests of her citizens and blockaded the port of Antofagasta. At this stage Peru, doubly concerned because of her secret alliance and because Chileans had acquired rights in her own nitrate fields in Tarapacá, offered her services as mediator, but no agreement could be reached and she became involved in the dispute herself, and, because of her more accessible situation, it fell to her lot to bear the chief burden of the defence in the war that followed. In spite of the heroic sacrifices of her officers and the desperate courage with which her soldiers fought, especially toward the last, in nearly every battle, on both land and sea, the Chileans were successful, and at last, when they had taken Lima itself and made their victory complete, the provinces in question were ceded to her provisionally and have been developed to their present importance under her protection. The half-breed descendants of the Aymaras and Incas, of which the rank and file of the Peruvian and Bolivian armies were composed, were no match for the virile _roto_, in whose veins flowed the fiery blood of the Basque and Biscayan pioneers, mingled with that of the spirited, warlike aborigines of Chile.