In the early 1940s, Brazil maintained a stance of neutrality in World War II, despite having economic ties with both the Allied and Axis powers. However, the situation changed dramatically when German submarines began targeting Brazilian merchant vessels in the South Atlantic. By mid-1942, this aggressive campaign culminated in the sinking of several ships, which led to rising public sentiment against the Axis powers. The attacks provoked outrage among the Brazilian populace and contributed to a growing desire for the nation to take a definitive stance in the war. On August 22, 1942, after considerable debate and pressure, President Getúlio Vargas announced Brazil's formal declaration of war against Germany, Italy, and Japan.

This declaration was not merely a symbolic gesture; it marked Brazil's active involvement in the Allied military campaign. Following the declaration, Brazil sent troops to fight in Italy as part of the Brazilian Expeditionary Force (FEB), which played a significant role in several key battles, including the Battle of Monte Castello. Brazil's entry into the war also facilitated closer relations with the United States, leading to economic and military collaboration that would shape Brazil's post-war development and its role on the global stage.