Monteserico Castle is situated on a hill in a strategic position for controlling commercial traffic on the Appian Way that passed nearby. First documented in 1041, the year of a famous battle between the Byzantines and the Normans, it became a domus during the Swabian period and a royal farmstead under the Angevins. The Monteserico Castle communicated with the Garagnone Castle and the Gravina Castle (commissioned by Frederick II) through signal torches to alert of approaching enemies.
Destroyed in the early 1500s, it underwent restoration in several phases from the 18th to the 19th century and has recently been the subject of restoration efforts.
In 1989, the municipality of Genzano di Lucania acquired ownership of the building.
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.