The village St. Mary's Church was probably built in the Early or High Middle Ages. It first appears in a historical record in 1228. It was rebuilt and expanded several times in the 13th to 15th centuries. The murals and stained glass date from the same period. The carved wooden ceiling was added around 1456. An ossuary was built under the church in 1481. In 1528 Bern adopted the new faith of the Protestant Reformation and spread it throughout its land. Zweisimmen, along with much of the Bernese Oberland initially resisted the new faith, but were forced to convert in the same year. The church was secularized and used for storage and meetings. In 1866 it became the Blankenburg village school.