The Battle of Rivas took place on April 11, 1856, during the conflict known as the Filibuster War in Central America. This battle was fought between the forces of the Nicaraguan leader William Walker and the allied troops of Costa Rica. Walker aimed to expand his control over Nicaragua, while Costa Rica sought to protect its sovereignty and prevent Walker's expansionist ambitions. The battle occurred near the town of Rivas, Nicaragua, and resulted in a decisive victory for the Costa Rican forces. This defeat significantly weakened Walker's position in the region and contributed to his eventual downfall, marking a turning point in the struggle against filibuster incursions in Central America.