Admiral of Pedro IV of Aragon, and Lord Steward of the Household of the king's third wife, Elionor of Sicily. Known for operating as a privateer. Was defeated by Pedro of Castile's fleet and executed in Seville. Mateo Merced Chronicle entries in which Mateo Mercer, Admiral of Aragon appears: Crónica de D. Pedro, ch. 26: 53-60