The early medieval Parish church of St. Martin Busskirch with its cemetery rests on the remains of a Roman building (1st to 4th century AD). It is one of the oldest churches around the Lake Zürich. Even the citizens of Rapperswil had to attend services in Busskirch until Count Rudolf II of Rapperswil built his own church and a chapel next to Rapperswil Castle in 1253.
In 1351 St. Martin Busskirch was incorporated by the monastery (until 1838). In co-operation with Jona the settlement formed an Allmendgenossenschaft (farmer's association), reigned by the Counts of Rapperswil, latter by the city of Rapperswil. In 1253 the parish churches of Rapperswil and Jona were established: St. Martin Busskirch lost its former importance and was in 1945 integrated in the Roman Catholic parish Rapperswil.
References:Visby Cathedral (also known as St. Mary’s Church) is the only survived medieval church in Visby. It was originally built for German merchants and inaugurated in 1225. Around the year 1350 the church was enlarged and converted into a basilica. The two-storey magazine was also added then above the nave as a warehouse for merchants.
Following the Reformation, the church was transformed into a parish church for the town of Visby. All other churches were abandoned. Shortly after the Reformation, in 1572, Gotland was made into its own Diocese, and the church designated its cathedral.
There is not much left of the original interior. The font is made of local red marble in the 13th century. The pulpit was made in Lübeck in 1684. There are 400 graves under the church floor.