The Counts of Rapperswil probably built a defense tower in the early 12th century on the site of today's Greifensee Castle. The beginnings of Greifensee Castle, which was partially destroyed in May 1444 (during the so-called Old Zürich War), date back to around 1250. The castle complex consisted of a Palas on a rock , which at the time stood directly on the lake shore and was protected on the other sides by a moat and ring wall. In 1520, the Zürich Council decided to rebuild the ruins to a modest castle.
After thorough renovation, the castle is now available to the public for conferences, seminars, lectures, presentations, receptions, courses, small concerts, exhibitions, cocktails and private events (banquets, weddings). You may also rent single rooms only.
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.