RepublicThe generals, supported by English weapons and troops, overthrew the monarchy in late 1889. Tired of economic stagnation and financial crises, the military decided to take matters into their own hands. While passing itself as a democracy, elections were rigged and oligarchies from the dominating states of São Paulo and Minas Gerais were the ones in charge, at the behest of the Army. The Army slowly began to increase its own power, eclipsing the church and even other branches of the military, like the Navy and National Guard. Despite having main bases in the coastal cities, the Army's members, beliefs, and commitments were felt across the country.
Brazil was still backwater and pre-industrial at the time and relied on industrial and technological products from the North Atlantic, but the British wanted a strong ally in South America as a counter to French-backed Argentina. With the aid of British loans, ideas, and advisors, Brazil turned itself around during the 1890s and early 1900s, with new factories and ports popping up in coastal cities. Modernized agriculture was introduced, and recently built railroads and telegrams connected the interior of the large nation to the coast. The Army itself modernized itself, featuring new British rifles and cannons. However, the industrial capabilities of Brazil would still be behind Argentina when World War I broke out.The attempted assassination of Archduke Karl of Austria-Hungary set off a chain of alliances, which led to war between Brazil and its allies versus Argentina and its allies. The initial Brazilian advances in 1915 into Argentina and the Rio de la Plata were stopped by the superior Argentine forces, and the Argentinians made slow progress to push the Brazilians out, though widespread trench warfare slowed them down. In 1918, a major Argentine offensive destroyed the weakened and tired Brazilian soldiers, forcing them out of Argentina and back into Brazil. During the rest of 1918 and early 1918 Argentina would win victories in Brazil and capture the major city of São Paulo, forcing Brazil to call for a ceasefire.