Complex sentence: The naval Battle of Abtao occurred on February 7 1866 between Spain and a combined Peruvian-Chilean fleet sent by Peruvian president Mariano Ignacio Prado, who had rallied the South Americans in defense against Spanish aggression.
Split into simpler sentences: The Naval Battle of Abtao took place on February 7 1866 between a Spanish naval squadron and a combined Peruvian-Chilean fleet. Sent by Peruvian president Mariano Ignacio Prado, who had rallied the South Americans in defense against Spanish aggression.