In 1365, he received a Papal Bull sanctioning his campaign as a crusade from Pope Urban V.[5] When he learned of a planned Egyptian attack against his Kingdom of Cyprus, he employed the same strategy of preemptive war that had been so successful against the Turks and redirected his military ambitions against Egypt.

In October 1365, Peter I set sail from Rhodes, himself commanding a sizable expeditionary force and a fleet of 165 ships, despite Venice's greater economic and political clout.

Landfall was made in Alexandria around 9 October, and over the next three days, Peter's army pillaged the city killing thousands and taking 5000 people to be enslaved.

[4] Peter had wanted to stay and hold the city and use it as a beachhead for more crusades into Egypt, but the majority of his barons refused, wishing only to leave with their loot.

Van Steenbergen's description of contemporary Muslim accounts, such as those of al-Nuwayrī al-Iskandarānī and Alī al-Maqrīzī, indicates that the crusading force succeeded partially thanks to superior diversionary tactics.