Kyburg Castle overlooks the Töss river some 3 km south-east of Winterthur. The first fortification at this site was likely built in the second half of the 10th century by the counts of Winterthur. It is first mentioned in 1027 under the name of Chuigeburg ('cows-fort'), which name points to an original use as a refuge castle for livestock.
The early castle was destroyed in 1028 or 1030 by emperor Conrad II. It was rebuilt and soon became the center of the county of Kyburg which was formed in 1053 as a possession of the counts of Dillingen. In 1079, during the Investiture Controversy, the castle was attacked and partially destroyed by Abbot Ulrich II of St. Gall. By 1096 the counts of Dillingen included count of Kyburg as one of their titles. By 1180, the counts of Kyburg emerged as a cadet line of the Dillingen family. They rose to be the most important noble family in the Swiss plateau beside the Habsburg and the House of Savoy by the 13th century.
After the death of the last count in 1264 Rudolph of Habsburg claimed the inheritance for his family. With one interruption the Imperial Regalia of the Holy Roman Empire were kept in the castle between 1273 and 1322.
The core of the extant castle originates in the 13th century, with the addition of substantial parts in the course of the 13th and 14th centuries. It is among the largest surviving medieval castle complexes in Switzerland, consisting of a bergfried and palas with additional residential and economic buildings and a chapel, all connected by a ring wall enclosing a large courtyard.
In the 1424 the city of Zürich bought the county, and the castle became the seat of the reeve. The dilapidated castle was substantially renovated at this time. The chapel has substantial late Gothic frescoes commissioned by Zürich. Substantial changes to the structure were made under reeve Hans Rudolf Lavater during 1527/8. Further changes were made to the structure in the early modern period.
The castle was plundered by the local populace in 1798, but it was again used as administrative seat from 1803 until 1831, when it was sold by auctio to one Franz Heinrich Hirzel of Winterthur who intended to use it as a quarry. To prevent its destruction, the castle was bought by the exiled Polish count Alexander Sobansky (1799–1861) in 1835. The Sobansky resided in the castle for the next 30 years. In 1917 the Canton of Zurich bought the castle back, since 1999 a society runs it, the Verein Museum Schloss Kyburg.
References:The Amphitheatre of the Three Gauls was part of the federal sanctuary of the three Gauls dedicated to the cult of Rome and Augustus celebrated by the 60 Gallic tribes when they gathered at Lugdunum (Lyon). The amphitheatre was built at the foot of the La Croix-Rousse hill at what was then the confluence of the Rhône and Saône.
Excavations have revealed a basement of three elliptical walls linked by cross-walls and a channel surrounding the oval central arena. The arena was slightly sloped, with the building"s south part supported by a now-vanished vault. The arena"s dimensions are 67,6m by 42m. This phase of the amphitheatre housed games which accompanied the imperial cult, with its low capacity (1,800 seats) being enough for delegations from the 60 Gallic tribes.
The amphitheatre was expanded at the start of the 2nd century. Two galleries were added around the old amphitheatre, raising its width from 25 metres to 105 metres and its capacity to about 20,000 seats. In so doing it made it a building open to the whole population of Lugdunum and its environs.