 Complete the following phrase:  Skirmishes and raids continued to occur in southern Italy. Aragonese guerillas attacked Catona and killed Peter of Alençon in January 1283; the Aragonese seized Reggio Calabria in February; and the Sicilian admiral, Roger of Lauria, annihilated a newly raised Provençal fleet at Malta in April. However, tensions arose between the Aragonese and the Sicilians and in May 1283 one of the leaders of the anti-Angevin rebellion, Walter of Caltagirone, was executed for his secret correspondence with Charless agents. Pope Martin declared the 