Alt-Signau castle was the ancestral home of the Barons of Signau. The family was first mentioned in 1130 when Werner von Signau appeared in a historical record. The castle was designed to protect and control the road between the Emmental and the Aare river. In the mid-14th century the castle was abandoned when the family moved to Neu-Signau Castle on a hill across the valley.
The ruin is relatively well preserved.
References: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.