Stadtpfarrkirche St. Johann church is located next to Rapperswil Castle. The castle and the parish church were built by Count Rudolf II and his son Rudolf III around 1220/29. The former parish church was located at Busskirch on upper Zürichsee lake shore, being one of the oldest churches around the lake area. Even the citizens of Rapperswil had to attend services in Busskirch until Count Rudolf II built his own parish church on he Herrenberg hill next to the castle. Legally, Rapperswil church was subordinated to 1253 the parish of St. Johann Busskirch and thus the Pfäfers abbey. In 1489 the adjacent Liebfrauenkapelle was built, the cemetery chapel that still exists. On 30 January 1881 the church was partially destroyed by fire, and rebuilt from 1881 to 1885.
The Romanesque hall church and the northern church tower were extended in 1383 to the west. In 1441 a smaller but massively southern church tower was built. Collection campaigns in 1493/97 allowed to rebuild the hall church into a tripartite Gothic choir with arched ceiling and tracery windows. Following the Reformation in Switzerland, two Renaissance wing altars in the side chapels were added respectively latter moved to other chappels. Thus, these altars were not destroyed by fire on January 30, 1882, as well as the sacristy located in the southern church tower, along with the precious treasure of the church: masterpieces by the goldsmiths Breny from Rapperswil, Dietrich, Dumeisen and Rüssi Ysenschlegel, being one of the richest in the Linth territory.
References:Celje Castle was once the largest fortification on Slovenian territory. The first fortified building on the site (a Romanesque palace) was built in the first half of the 13th century by the Counts of Heunburg from Carinthia on the stony outcrop on the western side of the ridge where the castle stands. It had five sides, or four plus the southern side, which was a natural defence. The first written records of the castle date back to between 1125 and 1137; it was probably built by Count Gunter. In the western section of the castle, there was a building with several floors. Remains of the walls of this palatium have survived. In the eastern section, there was an enclosed courtyard with large water reservoirs. The eastern wall, which protects the castle from its most exposed side, was around three metres thicker than the rest of the curtain wall. The wall was topped with a parapet and protected walkway.