At the end of the 14th century, Teutonic Knights built a castle in Ryn, serving as a base for fighting with the Lithuanians. Until 1525, the castle was the seat of the commander. After two years of the construction of the castle, then the Grand Master of the Order Winrich von Kniprode arrived in Ryn to inspect and take over the castle, and returned to the Malbork by waterway. In 1723 Ryn received city rights granted by the Prussian King Frederick William I and in 1853 the castle was converted into a prison. Since July 2006, the castle operates as a hotel.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.