Coetan Arthur dolmen, also known as Arthur's Quoit (not to be confused with Carreg Coetan Arthur, near Newport) is the remains of a Neolithic burial chamber (also known as a quoit). It dates from around 3000 BCE. The site, situated on the hillside close to St Davids Head in Pembrokeshire, Wales, is the collapsed chamber of what is presumed to be a passage grave which also has a round barrow. The massive capstone measures approximately 6 metres by 2.5 metres and is supported on one side by an orthostat approximately 1.5 metres in height.
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.