Brazil Declares War on Germany
Despite the then internal political conditions, Brazil entered into World War I in 1917, alongside with the Triple Entente, after initially adopting neutrality.
Brazil's contribution was modest, essentially little more than symbolic from a military perspective. Still, Brazil was the only South American country to participate in the war. Its primary contribution was in the naval war in the Atlantic, though it also sent a unit to the Western front.
On October 26, 1917, Brazil declares its decision to enter the First World War on the side of the Allied powers.
As a major player in the Atlantic trading market, Brazil—an immense country occupying nearly one-half of the entire South American continent—had been increasingly threatened by Germany’s policy of unrestricted submarine warfare over the course of the first two years of World War I. In February 1917, when Germany resumed that policy after temporarily suspending it due to pressure from neutral nations such as the United States, President Woodrow Wilson responded by immediately breaking diplomatic relations with Germany; the U.S. formally entered the war alongside the Allied powers on April 6, 1917.
The Great War at PBS