Brazil was engaged in a land campaign in Uruguay supporting the Colorado Party against the government in Montivideo. Paraguay had warned Brazil against such action and, encouraged by the poor performance of Brazil's troops in the field, became increasingly belligerent. On this day, in the River Paraguay, the Paraguayan navy seized the Brazilian vessel Marquês de Olinda, ostensibly to support the Uruguayan government. All diplomatic relations were broken off and a month later, Paraguayan army units invaded Brazil's western provinces. (By John Osborne)