St Tugual's Chapel dates back to the 11th century when the island was a haven for an order of Norman monks. However, there is evidence that the site has had religious significance since the 6th century. The chapel was designed in such a way that they could sit in the building's north nave without being seen by the public who would sit in the west portion of the chapel.
In the years before the Wood family took hold of the lease on the island, in 1949, the grounds around the west and south of the chapel had become overgrown and it was in their time that the churchyard come garden was made around the church.
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.