Mornas Fortress was already mentioned in the 9th century under the name of Rupea Morenata, the fortress, probably built in wood, was there to protect the village of Mornas. Built on a rocky outcrop, it offers incomparable views over the Rhône River. It was rebuilt of stone from the 12th century onwards.
Propriety of the Counts of Toulouse then the Papacy, Catholics and Protestants fought fiercely over it during the wars of religion. In 1562, after massacring the women, children and elderly in the chapel, the Protestants troops under the command of the cruel Baron des Adrets forced the Catholic garrison to throw themselves off the walls. This sadly notorious episode is called Sauto Barri ('wall jump'). The Huguenots met the same fate when the fortress was recaptured by the Catholics in 1568. After the French Revolution, the fortress was abandoned and fell to ruin.
Since 1978, the dynamic association Les Amis de la Forteresse has been restoring it and has brought it back to life as in medieval times, organizing fun pageant tours with the visitor being welcomed by knights and lords in period costume, for the pleasure of all, especially the children.
For those who want to continue their excursion, a cliff path winds along to the small Saint-Baudile Chapel.
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.