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:The Château du Lude is one of the many great châteaux of the Loire Valley in France. Le Lude is the most northerly château of the Loire Valley and one of the last important historic castles in France, still inhabited by the same family for the last 260 years. The château is testimony to four centuries of French architecture, as a stronghold transformed into an elegant house during the Renaissance and the 18th century. The monument is located in the valley of Le Loir. Its gardens have evolved throughout the centuries.