Central Americans Fight Back Against William Walker

On April 11, 1856, Costa Rican forces clashed with the private army of American filibuster William Walker in the streets of Rivas, Nicaragua. Walker had invaded Nicaragua the previous year, taking advantage of local political factionalism to seize influence across the country. His presence threatened neighboring Central American states as well as major international transport interests, particularly the lucrative transit corridor connecting the Atlantic and Pacific oceans through southern Nicaragua. In response to this expanding intervention, Costa Rican President Juan Rafael Mora mobilized the army and rallied civilian volunteers in March 1856, beginning a regional military campaign to expel the foreign force.

After Costa Rican forces won a swift victory at Santa Rosa, inside Costa Rica, on March 20, 1856, Walker's men retreated to Rivas, pursued by the Costa Ricans. Walker's men took shelter in the Guerra family mesón, a building at the corner of the town park near a church. Fierce fighting followed around the town square.