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:
Sirmione castle was built near the end of the 12th century as part of a defensive network surrounding Verona. The castle was maintained and extended first as part of the Veronese protection against their rivals in Milan and later under the control of the Venetian inland empire. The massive fortress is totally surrounded by water and has an inner porch which houses a Roman and Medieval lapidary. From the drawbridge, a staircase leads to the walkways above the walls, providing a marvellous view of the harbour that once sheltered the Scaliger fleet. The doors were fitted with a variety of locking systems, including a drawbridge for horses, carriages and pedestrians, a metal grate and, more recently, double hinged doors. Venice conquered Sirmione in 1405, immediately adopting provisions to render the fortress even more secure, fortifying its outer walls and widening the harbour.
Thanks to its strategical geographical location as a border outpost, Sirmione became a crucial defence and control garrison for the ruling nobles, retaining this function until the 16th century, when its role was taken up by Peschiera del Garda.