Rapperswil Castle was built in the early 13th century AD by the House of Rapperswil. It is surrounded on three sides by the Lake Zürich and by those upper section on the northwestern Seedamm area. Thus, the castle was well protected, dominating the old town of Rapperswil, and controlling the water way between Walensee and Lake Zürich on its most narrow part, as well as the medieval Gotthard Pass route between Lombardy and Zürich.
Rapperswil Castle dates back around 1200 to 1220, and it was first mentioned in 1229 on occasion of the foundation of the Rüti Abbey. The castle was built by Count Rudolf II and his son Rudolf III von Rapperswil, when the nobility of Rapperswil moved from Altendorf (Alt-Rapperswil) across the lake. As before in the 11th and 12th century AD, the family acted as Vogt of the Einsiedeln Abbey. Sandstone from the Lützelauisland was used to build the castle, the town walls and the city.
The first chapel was associated to the castle, but the chapel was located outside of its walls and separated by a trench. The preceding building of the Liebfrauenkapelle was built as an ossuary around 1220 to 1253.
In 1350 an attempted coup by the aristocratic opposition (a central person was Count Johann II) in the city of Zürich was forcefully put down, and the town walls of Rapperswil and the castle were destroyed by Rudolf Brun. Eis-zwei-Geissebei, a Carnival festival hold in Rapperswil on Shrove Tuesday, may go back to the siege and destruction of the city of Rapperswil. The battlements and the castle were rebuilt by Albrecht II, Duke of Austria in 1352/54.
After the extinction of the line of Habsburg-Laufenburg in 1442, the castle was given to the citizens of Rapperswil. Ending Old Zürich War, Rapperswil was controlled by the Swiss Confederation from 1458 to 1798 as a so-called Gemeine Herrschaft, i.e. under control of two cantons of the Old Swiss Conferation and their representant, a Vogt, and Rapperswil castle became an administration site respectively military base and prison.
Over the course of time, the castle fell into disrepair. In 1870 the castle was leased for 99 years from the local authorities by a post-November 1830 Uprising Polish émigré, Count Wladyslaw Broel-Plater, who had been in Switzerland since 1844. At his own expense he restored the castle, and on 23 October 1870 the Polish National Museum was established.References:
Steinvikholm Castle is an island fortress built between 1525 to 1532 by Norway's last Catholic archbishop, Olav Engelbrektsson. Steinvikholm castle became the most powerful fortification by the time it was built, and it is the largest construction raised in the Norwegian Middle Ages.
The castle occupies about half of the land on the rocky island. The absence of a spring meant that fresh water had to be brought from the mainland. A wooden bridge served as the only way to the island other than boat. Although the castle design was common across Europe in 1525, its medieval design was becoming obsolete because of the improved siege firepower offered by gunpowder and cannons.
The castle was constructed after Olav Engelbrektsson returned from a meeting with the Pope in Rome, presumably in anticipation of impending military-religious conflict. As Archbishop Engelbrektsson's resistance to the encroachment of Danish rule escalated, first with Frederick I of Denmark and his successor Christian III of Denmark, Steinvikholm Castle and Nidarholm Abbey became the Catholic Church's military strongholds in Norway. In April 1537, the Danish-Norwegian Reformation succeeded in driving the archbishop from the castle into exile in Lier in the Netherlands (now in Belgium), where he died on 7 February 1538. At the castle the archbishop left behind St. Olav's shrine and other treasures from Nidaros Cathedral (Trondheim). The original coffin containing St. Olav's body remained at Steinvikholm until it was returned to Nidaros Cathedral in 1564. Since 1568 St. Olav's grave in Nidaros has been unknown.
From the 17th to 19th century, the island was used as a quarry and some of its masonry was sold and removed from the site. This activity was condoned by the Danish-Norwegian authorities as a way of eliminating a monument to the opposition of the Danish–Norwegian Union.
Steinvikholm fort is owned and operated today by The society for the Preservation of Norwegian Ancient Monuments. The island has been the site of the midnight opera which details the life and struggles of the archbishop. The opera is held in August annually. The opera is organized by Steinvikholm Musikkteater since the beginning in 1993.