Borsh Castle (also known as Sopot Castle) dates from Antiquity, and its fortifications follow the trace of an acropolis, with four subsequent phases of reconstruction, ranging from the early Byzantine period to the late Middle Ages.
The site is first mentioned in the early 13th century, when archbishop Demetrios Chomatenos wrote of the 'archonship of Sopotos', part of the region of Vagenetia. In 1258, the Despot of Epirus Michael II Komnenos Doukas gave the castle along with Buthrotum and the island of Corfu as dowry for his daughter Helena to Manfred, King of Sicily. It came back under Epirote control soon thereafter, before being once again ceded by Nikephoros I Komnenos Doukas to Charles I of Anjou in 1279. The area returned again to Epirote hands in the subsequent decades, but in the Epirote rebellion against Palaiologan Byzantine rule in 1338–39, it remained loyal to Emperor Andronikos III Palaiologos.
Following the Ottoman conquest, a cadaster from 1431 lists Sopot with 60 households, and as capital of a nahiye. In 1456, troops of King Alfonso V of Aragon were operating in the area of Sobato against the Ottomans. In 1470 it was under Venetian control, under the jurisdiction of the governor of Corfu; at the end of the Ottoman–Venetian War of 1463–1479, the Ottomans laid claim to it and apparently received it, for in 1488 the local Albanian population rebelled against Ottoman rule.
The walls of the castle, which follow the ancient fortifications, survive. In the interior, the medieval fortress was divided through a wall in two. Triangular towers were added later, probably during the middle Byzantine period. In the interior of the castle stand ruins of various buildings and cisterns.
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.