The Rio Castle in opposition to its counterpart, the Castle of Rumelia at Antirrio, is located at the north tip of the Rio peninsula in Achaea, Greece, at the entrance of the Corinthian Gulf. The Rio-Antirio Bridge is located next to it, and the local ferry docks lie on either side. Today it is used for cultural purposes, especially concerts and is a tourist attraction.
The castle was built by the Ottoman Sultan Bayezid II in 1499 above the ruins of an ancient temple of Poseidon, within three months. Along with its twin, the Antirrio Castle, they were intended to protect the entrance to the Corinthian Gulf, and were nicknamed the 'Little Dardanelles'. The castle is located on the sea shore, with its northern side protected by the sea and the southern by a broad moat, filled with sea water, and two outer bastions (ravelins), linked to the main fort by stone bridges. It has two gates, the central one, facing landwards, and the sea gate.
In 1533, it was briefly captured by the Genoese under Andrea Doria, but the Ottomans recaptured it later in the year. In 1687, during the Morean War, it was taken by the Venetians under Francesco Morosini. The Venetians rebuilt the castle, restoring and strengthening it by the addition of towers, giving it its final shape. The Venetians also added the small chapel of the Life-giving Spring. The Ottomans retook it in 1715, and remained until they surrendered it to French General Nicolas Joseph Maison. Between 1831 and 1912, the castle was used as a military and then civilian prison, whose inmates were often used by the municipality of Patras for cleaning the streets of Rio.
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.