The brief Alexandrian Crusade occurred in October of 1365 and was led by Peter I of Cyprus against Alexandria. Almost completely devoid of religious impetus, it differs from the more prominent Crusades in that it seems to have been motivated entirely by economic interests.
Peter I spent three years, from 1362 to 1365, amassing an army and seeking financial support for a Crusade from the wealthiest courts of the day. 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. From Venice, he arranged for his naval fleet and ground forces to assemble at the Crusader stronghold of Rhodes, where they were joined by the Knights of the Order of St. John.
In October of 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 October 9, and over the next three days, Peter's army conquered and looted the city before permanently withdrawing on October 12 against Mamluk forces.
Peter himself understood that Alexandria would have been impossible to rule, given its great distance from Cyprus.
Jo van Steenbergen, citing Peter Edbury, argues that the crusade was primarily an economic quest. Peter wanted to end the primacy of Alexandria as a port in the Eastern Mediterranean in the hope that Famagusta would then benefit from the redirected trade.  Religious concerns, then, were secondary.
Van Steenbergen's description of contemporary Muslim accounts, such as that of Alī al-Maqrīzī, indicates that the crusading force succeeded partially thanks to superior diversionary tactics. The Alexandrian defensive force occupied itself fighting in the area around the western harbor, while the "real" force, including cavalry, made landfall elsewhere in the city, apparently hiding in a graveyard, undetected by the defenders. The crusading force was thus able to attack from both the front and the rear, panicking the Alexandrians, who did not recover from this setback.