Roger de Loria, a Sicilian admiral in Aragonese service, is the son of Richard of Lauria, Great Justiciar of the Kingdom of Sicily, and Donna Bella, a nurse of Constance of Hohenstaufen.

His father had served under King Manfred of Sicily; when the last member of that family, Conradin of Swabia, was beheaded at Naples in 1268, he had taken refuge with other Ghibelline exiles at Barcelona, part of the Kingdom of Aragón, with his mother.

Peter III of Aragon, who had married Constance of Hohenstaufen, later made him knight together with Corrado Lancia, who is to be a comrade of Roger in many of his enterprises.

In 1282, Roger had been named commander of the Aragonese fleet, a charge he will retain under Peter's successors James II and Frederick III.

Roger of Lauria had commanded the Aragonese fleet during the campaign to capture Sicily from the Angevins after the Sicilian Vespers revolt in 1282, which made the Aragonese rulers of Sicily.

Charles of Salerno, in the absence of his father Charles I of Naples, had sent the Provençal fleet to relieve the besieged garrison of Malta, which is trapped in the Castello del Mare (the "Castle of the Sea", now known as Fort St. Angelo) in Grand Harbour after the inhabitants of Malta had revolted.

Roger, learning of this, sends his own fleet to support the Maltese.

Arriving at night on July 7-8, 1283,he makes contact with a besieger and sends a sentry boat into the harbor.

It is reported that the Angevin galleys are beached under the castle walls.

Roger moves his galleys into line abreast at the entrance to the harbor, silencing the guard boats in the process, and connects his ships together.

At about dawn, he orders a trumpet challenge to be sounded.

His reason for doing this is not clear.

Perhaps he wanted to show the bravery and boldness of his crews, or to prevent anyone from saying he couldn't have won if the enemy hadn't been asleep, but since he later attacked a sleeping enemy, it would seem that he did it to draw the Angevins out to his prepared position.

It would have been difficult for him to attack in the confines of the harbor, and he would in any event have lost the element of surprise.

Also, beached galleys are almost impossible to defeat in close combat, as they can be continually reinforced from shore.

The Angevin crews rush to launch their galleys, and move out in a disorganized manner.

Roger first deploys his Catalan archers, then closes for hand-to-hand combat.

Angevin commander William Cornut is killed by Roger in single combat when he boarded Roger's flagship, but his co-commander Bartholomew Bonvin breaks through the line with some galleys and escapes.

About ten galleys are captured.