Brazil during World War I Brazil , during World War I ( 1914 - 1918 ) , initially adopted a neutral position , in accordance with the Hague Convention , in an attempt to maintain the markets for its export products , mainly coffee , latex and industrial manufactured items . However , following repeated sinking of Brazilian merchant ships by German submarines , in 1917 the Brazilian President Venceslau Brás declared war against the Central Powers , and was the only country of Latin America to be directly involved in the war . The major participation was the Navy ' s patrol of areas of the Atlantic Ocean . Initial phase . Brazil officially declared neutrality on August 4 , 1914 . At the beginning of the war , although neutral , Brazil faced a complicated social and economic situation . Its economy was largely based on exports of agricultural products such as coffee , latex , and very limited industrial manufacturing . As these products exported by Brazil were not considered essential by foreign consumers , customs duties and export fees ( the main source of government income ) decreased as the conflict continued . This was accentuated further by the German blockade of Allied ports , and then by a British ban on the importation of coffee into England , in 1917 . This arose because the British government now considered the cargo space on ships necessary for more vital goods , given the great losses of merchant ships as a result of German attacks . The Brazilian merchant ship " Rio Branco " was sunk by a German submarine on May 3 , 1916 , but as this was in restricted waters and registered under the British flag and with most of its crew composed of Norwegians , it was not considered an illegal attack by the Brazilian government , despite the public uproar the event caused . Relations between Brazil and the German Empire were shaken by the German decision to introduce unrestricted submarine warfare , allowing its submarines to sink any ship that breached the blockade . On April 5 , 1917 , the large Brazilian steamship " Paraná " ( 4 , 466 tons ) , loaded with coffee and travelling in accordance with the demands made on neutral countries , was torpedoed by a German submarine with three Brazilians being killed . Protests . When news of the sinking of the " Paraná " arrived in Brazil a few days later , several protests erupted in the capital . The Minister of Foreign Relations , Lauro Müller , a citizen of German origin with a pro - neutrality position , was forced to resign . In Porto Alegre , marches were organized with thousands of people , initially peaceful . Later , the demonstrators began attacking shops and properties owned by ethnic Germans or their descendants , like the Hotel Schmidt , the Germany Society , the club and the newspaper " Deutsche Zeitung " , and the Turnerbund , which were raided , looted and torched . On 1 November 1917 , an enraged mob damaged houses , clubs and factories in Petropolis , including the restaurant Brahma ( completely destroyed ) , the Gesellschaft Germania , the German school , the company Arp , and the " German Journal " , among others . At the same time , in other cities there were minor demonstrations . Episodes with violence repeated until Brazil ' s declaration of war against Germany and its allies in October 1917 . Although the nationalist and pro - war demonstrations intensified over 1917 , they never surpassed the anti - war and anti - militarist demonstrations led by trade unionists , anarchists and pacifists , who opposed the war and accused the government of diverting attention from internal problems , sometimes coming into conflict with nationalist groups that supported Brazil ' s active participation in the war . Violent repression followed a general strike late in 1917 , and the declaration of war in October also served as a means to declare a state of emergency and persecute opponents . Military involvement . Calogeras Plan . Although the administration of Venceslau Brás , which was to end in his last year in office , had made statements implying that it did not intend to involve the country deeper into the conflict ; in early 1918 , a confidential report commissioned by presidential candidate elected that year , Rodrigues Alves was completed . This report , coordinated by the parliamentary expert on foreign policy and military affairs , João Pandiá Calogeras , regarding the entry of Brazil in the conflict , recommended that country should send an expeditionary force of considerable size to fight in the war , using all necessary means ( including ships of enemy powers already seized in Brazilian waters and ports ) to disembark the troops on French soil where they would be trained and equipped by the French , all financed with US bank loans , which in turn would be settled by compensation imposed on the defeated enemies after the war . The Calogeras Plan ( which was only made public after the death of its authors ) contained several proposals for the new elected administration ( that would take office in November of that year ) , across several government areas . Referring to the country ' s participation in the conflict , the plan was not dependent on the lack of military - industrial infrastructure that was a feature of the country at that time . However , the direction taken by internal and external events that year , as well as the specific circumstances of Brazilian politics ( then including opposition from the population to war ) and the lack of a clear foreign policy , prevented it be carried forward , precluding the country from having greater involvement in the conflict . Army . Brazilian participation in land operations was limited to a preparatory military mission of sergeants and officers , which was sent to Europe in mid - 1918 , and whose members were attached to allied units , mainly in the French Army , to gain awareness of modern techniques employed in organizing and fighting in Western Front . The end of the conflict at November 1918 precluded the further development of the country ' s military involvement in the war , as envisioned in the Calogeras Plan . One - third of the officers who were sent to France , were promoted for their courage in battle . Among them were the then Lieutenant José Pessoa Cavalcanti de Albuquerque , who throughout his career became an important ideologue and reformer of Brazilian Army , and Major Tertuliano Potyguara , a controversial figure accused of war crime s in the Contestado campaign , who was wounded in action at Battle of St . Quentin Canal , during the Meuse - Argonne Offensive . Navy . Brazil ' s main military involvement in this conflict took place at sea . To fulfill this mission , the Secretary of Navy ordered the use of part of its naval power in the anti - submarine campaign , with Admiral Alexandre Faria de Alencar organising a task force that would allow the effective participation of the Brazilian Navy in World War I . Ministerial Notice No . 501 was issued on January 30 , 1918 , establishing the " Naval Division for War Operations ( Divisão Naval em Operações de Guerra - DNOG ) " , a Naval fleet composed of units drawn from the fleets that formed the Navy in Brazil . The dreadnought s and , two scout cruisers , and were some of the major warships of the DNOG . The DNOG was composed of the following vessels : The DNOG was initially tasked to patrol the Atlantic maritime area covered by the triangle between the city of Dakar on the African coast , the island of São Vicente , Cape Verde and Gibraltar at the entrance to the Mediterranean . The Division would remain under the orders of the British Admiralty , represented by Admiral Hischcot Grant . As Commander , the Minister appointed one of the most well - regarded officers at the time , Admiral Pedro Max Fernando Frontin , appointed on January 30 , 1918 . The war at sea fought by Brazil ' s navy began on August 1 , 1918 following the departure of the force from the port of Rio de Janeiro . On August 3 , 1918 , the Brazilian ship " Maceió " was torpedoed by the German submarine U - 43 . On August 9 , 1918 , the mission reached Freetown in Sierra Leone , staying 14 days , where the crew began falling ill with Spanish flu during a pandemic . On the night of August 25 , while sailing from Freetown to Dakar , the division suffered a torpedo attack made by German submarines , but no casualties or damage were suffered by the Brazilian vessels , the torpedoes passing harmlessly between the Brazilian ships . A successful counter - attack using depth charge s was launched , the Royal Navy crediting the Brazilians with the destruction of a U - boat . Subsequently , after anchoring in the port of Dakar , the crews were again severely hit by Spanish flu , which claimed the lives of over a hundred sailors and kept the Division restricted to port for almost two months . Among the Allied naval command , there was debate about how the forces of the Brazilian fleet should be used ; “ The Italians wanted them in the Mediterranean , the Americans wanted them to work closely with US forces , and the French wanted to keep them protecting the commercial maritime traffic along the African coast Between Dakar and Gibraltar “ . This indecision amongst the Allied command , combined with operational problems and the Spanish flu pandemic led to extended delays . In the event , the fleet did not arrive at Gibraltar until the beginning of November 1918 , only to see the armistice signed within days , ending to World War I . The Navy also sent to the Western Front , as another preparatory military mission , a group of military aviators who served with the RAF . Military medical mission . On August 18 , 1918 the Brazilian Medical Mission , led by Dr . Nabuco Gouveia and directed by General Aché , was established with 86 doctors , as well as civilian pharmacists , administrative support staff and a security platoon , and sent to the European Theatre in order to establish a hospital . On September 24 , 1918 the Mission landed at the French port of Marseille and gave support to the French people against a flu outbreak which ravaged that country , ensuring the continuity of logistical support to the troops at the front . The Medical Mission was terminated in February 1919 . Aftermath . After the war ' s end , Brazil participated in the Versailles Peace Conference , with a delegation led by future president Epitácio Pessoa . Brazil was also a founder of the League of Nations after the end of the war . Upon returning to Brazil , the Naval Division ( DNOG ) was dissolved on June 25 , 1919 , having complied fully with its entrusted mission . The Treaty of Versailles allowed Brazil to keep over 70 ships that it had seized from the Central Powers during the war , and which were then incorporated into the Brazilian merchant fleet . Brazil was also financially compensated by Germany for the lost coffee shipments and ships that were sunk by German U - boats during the war . From an economic point of view , although exports of latex and coffee fell sharply at first , creating a crisis in the economy , as the conflict continued , Brazil eventually began to find good trading opportunities . Increased international demand for foodstuffs and raw materials forced the country to change its economic structure away from the predominant agriculture . It was then that Brazil underwent unprecedented industrial development , also making use of immigrant labour , composed largely of Europeans initially fleeing famine and then the war . The number of factories quadrupled in the war years , doubling the number of workers . Brazil decreased the number of imported items , changing the country ' s socioeconomic face .