Porto Palermo Castle was probably built by the Venetians as it could be relieved by sea and it has the same triangular plan with round towers found in the Venetian fort at Butrint. At that time the identity of its builders ought to have been clear, from a plaque above the entrance gate. This plaque is now missing but the weathering of the stones clearly shows that it has not been missing for many decades. Almost certainly this plaque had a carving of the lion of St. Mark. The most plausible explanation of the error found in the guide books is a rewriting of history in the communist period. Re-ascribing a colonial legacy to construction by an Albanian fits a nationalist isolationist agenda.
The castle would have been vulnerable to cannon fire from the hill above and this also suggests an early date for its construction when cannon had not developed the range they had later. In 1662 the Venetians feared the Turks would recondition it. In 1803 Ali Pasha offered the castle and port to the Royal Navy. At which time the fort only had 4 or 5 cannon implying that Ali Pasha did not see the fort as important for him.
References:The Château de Foix dominates the town of Foix. An important tourist site, it is known as a centre of the Cathars. Built on an older 7th-century fortification, the castle is known from 987. In 1002, it was mentioned in the will of Roger I, Count of Carcassonne, who bequeathed the fortress to his youngest child, Bernard. In effect, the family ruling over the region were installed here which allowed them to control access to the upper Ariège valley and to keep surveillance from this strategic point over the lower land, protected behind impregnable walls.
In 1034, the castle became capital of the County of Foix and played a decisive role in medieval military history. During the two following centuries, the castle was home to Counts with shining personalities who became the soul of the Occitan resistance during the crusade against the Albigensians.