The Martinikerk (Martin's church) is the oldest church in Groningen. The church and its associated tower (the Martinitoren) are named after Saint Martin of Tours (316–397), the patron saint of the Bishopric of Utrecht to which Groningen belonged. The church was a cathedral for a short period during the first bishopric of Groningen (1559–1594).
The origins of the Martinikerk are a cruciform church built in the 13th century, which was extended in the 15th and 16th centuries. It contains several 16th century tombs and Wessel Gansfort's 18th century tomb. Much of the wall and roof paintwork has been preserved. Of particular note is a 16th-century depiction of the life of Jesus Christ.
The tower was built from 1469 till 1482, with later additions. Citizens of Groningen often refer to the tower as d'Olle Grieze (Old Grey One). The original 13th century tower was destroyed by lightning and a new tower was built in the 15th century, also destroyed by lightning.
References:Since I can’t be there, maybe someone would be interested in taking a video of where the Organ is situated; then kindly uploading it to YouTube, for instance.
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.