The Church of St Teilo is the parish church of Llantilio Pertholey. The church is thirteenth century in origin with significant additions in the sixteenth century, a major restoration in 1890 and further minor restoration in the twentieth century. The tower is of the early fourteenth century and the aisle of slightly later date. Around the chancel are three chantry chapels. The bell tower holds six bells, dating from the seventeenth century.
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.