The first wooden church of Kambja was built probably in the beginning of the 14th century. Churches were destroyed and rebuilt several times during centuries. The present Lutheran St. Martin’s Church was originally rebuilt in 1720, this time of stone and a transept was added to the old part in 1874. After World War II, the church, which is one of the biggest in Southern Estonia, was in ruins for many years until restoration began in 1989. The old bells which were cast in Moscow have survived. A new organ was donated by the Träsiövi congregation of Sweden.
The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.