The Milan amphitheatre was built near the Porta Ticinese in the 2nd-3rd centuries AD when Mediolanum grew as economical and political importance while Rome declined. It remained in use until the city was one of the capitals of the Western Roman Empire (4th or 5th centuries). Later it was abandoned after Christianity imposed an end to arena games, but also as, in the wake of the imperial crisis, animals to be used in the amphitheatre were no longer imported. It became a quarry for construction stones as early as the 4th century AD, when the Basilica of San Lorenzo was built.
The edifice was demolished during a Barbarian attack on Milan, as it was located outside the walls and could therefore be used as stronghold by the attackers. The date of the event is uncertain, however: it could be 402, during the Visigothic invasion of Italy, or in 452, when northern Italy was ravaged by Attila, or during the Gothic Wars (6th century).
The scanty remains of the amphitheatre have, however, allowed the archaeologists to calculate that it was 129.5 metres long and 109.3 metres wide.
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.