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:Rosenborg Palace was built in the period 1606-34 as Christian IV’s summerhouse just outside the ramparts of Copenhagen. Christian IV was very fond of the palace and often stayed at the castle when he resided in Copenhagen, and it was here that he died in 1648. After his death, the palace passed to his son King Frederik III, who together with his queen, Sophie Amalie, carried out several types of modernisation.
The last king who used the place as a residence was Frederik IV, and around 1720, Rosenborg was abandoned in favor of Frederiksborg Palace.Through the 1700s, considerable art treasures were collected at Rosenborg Castle, among other things items from the estates of deceased royalty and from Christiansborg after the fire there in 1794.
Soon the idea of a museum arose, and that was realised in 1833, which is The Royal Danish Collection’s official year of establishment.