The walls of the ancient Fishermen's Chapel are reputed to date from the middle of the 6th century, but some authorities give a later date. It is however only a few monastic chapels survived the destruction of over fifty others at the hands of the Reformers in the 16th century. The material used in the chapel is the same as was used in the parish church: limpet shells crushed and dissolved with boiling sea-water. The stone roof was raised in the 14th century. The monks of that period evidently found the roof too low and squat for wall paintings. These were discovered in 1918. After a severe storm, colour was revealed on the ceiling and a picture of the 'Assumption' was seen, but in a damaged condition. But underneath the plaster was found another painting, 'The Annunciation', of about 1310-1315 A.D. At the foot of this painting are seen fourteen figures, supposedly members of an old Jersey family, the head of which had paid for this painting.The floor was restored to its earlier level in the 1980s to the medieval level, and the 'low, squat' aspect of the chapel which appears in early photographs is now gone, as the proper proportions can be seen.
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.