Treaty of the Triple Alliance The Treaty of the Triple Alliance was a treaty which allied Brazil , Argentina , and Uruguay in the Paraguayan War . Signed at the beginning of the war , its articles prescribed the allies ' actions both during and after the war . Content . Legal Restrictions . Free navigation of the Paraguay River had been an issue between Paraguay and Brazil since the presidency of Carlos Antonio López who resented having been forced to grant Brazil free navigation rights on the river in 1858 . As a result , article 11 of the treaty stipulated that " the allies shall proceed to make the necessary arrangements with the constituted authorities , as to ensure the free navigation of the Parana and Paraguay Rivers , in a way that the rules and laws of that republic would not obstacle , impede or tax the direct transit and navigation of the merchant or war ships of the Allied States , which are headed to their respective territories or dominions which do not belong to Paraguay , and shall take the convenient guarantees towards the effectiveness of said arrangements " thus ensuring that Paraguay had no more control over Brazilian and Argentinian ships which desired to co - use both the Paraná and Paraguay rivers . Article 14 established that Paraguay would be held accountable for the entire war effort of all four nations and as such had to cover for the expenses of the entire war . This article includes not only governmental expenses , but also damages to private property . This sent Paraguay , who until that moment had no external debt , into an enormous debt with respect to the three allied countries . This problem was exacerbated by the fact that Paraguay was ransacked during the war having all valuable furniture , jewelry and gold of all kind taken by the allies and auctioned in their respective countries ; also , after the war , the country was so devastated both economically and demographically , that there were hardly anyone left to work the land and produce anything in the country without foreign aid . Article 17 determined that the treaty would remain valid and enforceable even after the war ended with such strength that also allowed the allies to take any means to ensure the full compliance of the new Paraguayan government to these articles , should it desire to modify any of them . Finally , article 6 in the secret treaty stated that " The allies solemnly commit themselves not to abandon arms unless commonly agreed , and as long as they haven ’ t overthrown the current government of Paraguay , as well as not to try separately , nor sign any peace treaty , truce , armistice which would put an end to or suspend the war , unless agreed by all parties . " This not only rendered truce or peace nearly impossible but also stipulated that the war was to continue until the current government ceased to be , which meant the death of López . Territorial Changes . Territorial disputes before the war . The borders between Argentina , Bolivia and Paraguay were hotly contested before the war . After gaining their independence from Spain , there was no longer an authoritative definition of these Latin American nations ' borders . This created a considerable dispute regarding the borders between Argentina and Paraguay since they both belonged to the Viceroyalty of the Río de la Plata , which had been seated in Buenos Aires . As a result , Argentina , upon their independence which was a year before the Paraguayan , had planned to annex Paraguay , who had declared its independence five years before the Argentines ' despite having secured their independence a year later , as a province . After Brazil gained its independence from Portugal on September 7 , 1822 , the newly independent country sent a commissioner to the Paraguayan government of Dr . Francia on August 24 , 1824 who promised that Brazil would recognize the independence of Paraguay , which happened on September 14 , 1844 . Brazil recognized during this event that the national limits with Paraguay would be those established by the San Ildefonso Treaty of 1777 . In 1850 , a treaty was signed between Brazil and Paraguay which mentioned the preservation of the " statu quo " regarding these limits ; however , after Argentine and Paraguayan relations improved , one effect was the worsening of the relations with Brazil , which led Brazil to send 20 war ships into Paraguayan territory . Carlos Antonio López , then president , sent his son , Francisco Solano López in , to quality as a diplomat , to sign a treaty which set the date for the finalized limits of the war , a year from the signing . When diplomats of both nations got together to set the limits , an agreement couldn ' t be reached , which postponed the setting another 5 years . During this time , Brazil never stopped going deeper into Paraguayan territory . Territorial Changes in the Treaty . In the article 16 of the treaty , the allies proposed a definite distribution of the Paraguayan territory , according to which Argentina would receive the entirety of the Gran Chaco and Brazil would get a big area of territory of the north - eastern Paraguay . While Brazil did take the territory the treaty entitled them to , Argentina couldn ' t finish occupying the chaco territory . Fulfilment of Treaty . Brazil . The Perpetual Peace and Friendship between the Republic of Paraguay and the Empire of Brazil was signed in Asuncion on January 9 , 1872 . In it , Paraguay recognized as debt to Brazil all damages caused to Brazilian people and cities at an interest of 6 % with an annual amortization of 1 % . All waters of the Paraguay , Parana and Uruguay rivers were open for trade and navigation . Brazil also reserved the right to occupy Paraguay with a part of the imperial army in order to maintain peace and ensure that all terms of the treaty were complied with . The national limits between Paraguay and Brazil were established in three different treaties . On the treaty signed on January 9 , 1872 the limits were set to be these : the riverbed of the Paraná River from Yguasu ' s mouth up to Parana ' s Seven Falls waterfall or Guaira Falls ; from the Guaira Falls , by the summit of the Mbaracayu Range and later by Amambay ' s up to Apa River ' s source , from where it follows its riverbed down to its mouth on the eastern shore of the Paraguay River . On January 16 , 1872 another treaty was signed where the release of all deserters , prisoners and criminals of war was established . Two days later on the 18 a new treaty of Friendship , Commerce and Navigation was signed . By the January 7 , 1874 protocol , the Estrella stream was considered the Apa River ' s source . Finally , a last definite treaty was signed on May 21 , 1927 in Rio de Janeiro which was a complement to the January 9 , 1872 one . It established that the limit between both countries was the riverbed of the Paraguay river from the mouth of the Apa River with the Paraguay River up to its mouth in Bahia Negra , with the western shore being Paraguayan territory and the eastern , Brazilian . Uruguay . A treaty of Peace , Commerce and Navigation was signed on December 13 , 1873 between Paraguay and Uruguay . As with the Brazilian treaty , Paraguay recognized the expenses , damages and detriments of Uruguayan campaign . Both governments also committed to return all prisoners of war and open to commerce both nation ' s rivers . Argentina . A Treaty of Peace with Argentina was signed on February 3 , 1876 between Paraguay and Argentina . In it , Paraguay recognized all war expenses as well as the damages and detriments caused to Argentine public and private property . The Navigation and transit of the Paraguay , Parana and Uruguay River was also opened . The National Limits between both nations was established like this : The main riverbed of the Parana River , from the Yguasy mouth up to its meeting with the Paraguay River ; and from the meeting of Paraguay River with Pilcomayo River , following this river ' s main riverbed leaving thus the Central Chaco region as Argentine territory . The territory between the main Pilcomayo riverbed up to Bahia Negra was divided in two sections , having the first one ( from the Verde River – 23° 10 ' Latitude South ) was granted to Paraguay , and the second one was submitted to an arbiter designed by both governments . The arbiter chosen by both nations was U . S . President Rutherford B . Hayes , who on November 12 , 1878 recognized the just and legal title of Paraguay to the territory between the Pilcomayo River and the Verde River . On May 14 , 1879 the Argentine armed forces left the Chaco Boreal region . In honour of President Hayes , the Presidente Hayes Department , the largest department in the nation , is named .