There was originally a Roman castellum (Castellum Laurum) in Woerden, as part of the limes of the Roman Empire and thus part of the defense lines of the northern border of the Roman Empire. The first castellum was built in the 40s AD, and was destroyed in 69 AD during the Batavian rebellion. In 70 AD the castellum was rebuilt, and the Romans remained until 402 AD, with an interruption lasting from about 275-300 AD. The Castellum was located at the present site of the medieval Petruschurch and surrounding church yard. During construction work on a new underground parking facility in the city center of Woerden, the remains of numerous old Roman buildings and a Roman cargo ship were found.
The current castle was built in around 1160 by bishop Godfrey van Rhenen. Due to its strategic location on the border between the County of Holland and the Bishopric of Utrecht, various wars have been fought in and around Woerden. In 1410 John III, Duke of Bavaria-Straubing reconstructed the castle.
Until the 19th century the castle was used as a prison. There's even a pit prison in the northwest tower, which was used for unruly prisoners. In the 20th century the castle was part of military barracks and used for storage of all kinds of goods but poorly maintained. This caused severe decay. Today it is restored as a restaurant.
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.