The castle complex on the Willibaldsberg was begun in 1355 and extended in the second half of the 16th century under Martin von Schaumberg. It was transformed into an impressive residence by Elias Holl during the reign of Prince-Bishop Johann Conrad von Gemmingen (1595-1612) – at this stage of the building's history the towers were crowned by onion domes.
Gemmingen also laid out the renowned botanical garden Hortus Eystettensis. Based on the copperplate engravings illustrating the plant collection which were created in 1613 by Basilius Besler, the Bastion Garden opened in 1998 reproduces the plant world of the original botanical garden.References:
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.