Bischofszell castle was built in the 12th/13th century. It was damaged by the city fire in 1419 and repaired soon thereafter. During the 17th and 18th century the castle was expanded and totally renovated. The newly founded Canton of Thurgau took over the castle in 1798, but sold it in 1811 again. About 1838 the west part collapsed, and in 1843 the keep was broken up. Since 1930, the castle has been owned by the municipality.
The old bridge, constructed in late gothic style, was inaugurated in 1487. It is the oldest bridge in the entire region.
Built around AD 90 to entertain the legionaries stationed at the fort of Caerleon (Isca), the impressive amphitheatre was the Roman equivalent of today’s multiplex cinema. Wooden benches provided seating for up to 6,000 spectators, who would gather to watch bloodthirsty displays featuring gladiatorial combat and exotic wild animals.
Long after the Romans left, the amphitheatre took on a new life in Arthurian legend. Geoffrey of Monmouth, the somewhat imaginative 12th-century scholar, wrote in his History of the Kings of Britain that Arthur was crowned in Caerleon and that the ruined amphitheatre was actually the remains of King Arthur’s Round Table.
Today it is the most complete Roman amphitheatre in Britain.