Matthew of Moncada was count of Aderno and Agosta, the grand seneschal of the Kingdom of Sicily under Frederick the Simple.
[1] He was the son of William Raymond II of Moncada and his wife, Margaret Sclafani.
The inhabitants of the duchy sent a delegation to the King, who in August 1363 appointed Matthew to the post—reportedly for life—with the task of restoring order.
[2] As Roger de Llúria was also engaged in a conflict with the Venetian colony of Negroponte, and due to the danger posed by his Turkish troops to all Christian states of Greece, a coalition comprising Venice, the Knights Hospitaller, the Principality of Achaea, and the Byzantine province of Mystras had formed, which defeated Roger's Turks in a naval battle off Megara and forced him to come to terms in 1365.
[3] Despite the fact that the Catalan lords of Athens were now willing to affirm their submission to the King, Moncada was reluctant to go to Greece, where the situation was unstable and perilous; as a result, King Frederick was forced to legitimize Roger de Llúria's power and acknowledge him as vicar-general in late 1366.