The ruins of a castle on the little island Agios Nikcolaos in the artificial Kremaston lake, near the point where the river Acheloos (the main watersource of the dam) discharges into the lake.

The castle is close to the village Pratovouni. Sivista was another village close to the castle which now is covered by the waters.

Part of the external yard of the castle is also under the waters.

On the islet of Ai-Nicolas there are two separate fortifications (see plan, above). Firstly, there is an ancient outer wall that protected the vulnerable south-eastern side of the hill (hereafter referred to as the “south-eastern fortification”), and secondly, there is also a small citadel at the top of the hill which was medieval (hereafter “medieval castle”).

Location & Strategic Scope

It is obvious that the morphology of the area has changed drastically compared to that of the Middle Ages, due to the creation of the artificial lake of Kremasta in the 1960s. In the past, the castle was not located on an island, but on a steep prominent hill in a strategic point.
It was located at the exit of the Acheloos gorge towards the fertile valley (now covered by water).
Due to the steep rocks, the gorge and the surrounding Acheloos river, the hill had strong natural protection. Only one part of the hill was vulnerable, on its southeast side where there was a plateau. As expected, this part was fortified. It was protected by the “south-eastern fortification”.

History

The castle is not mentioned by historical sources. The only reference from travelers is from W. M. Leake, in the early 19th century, who recorded a large ruined castle called “Syvisti” in the area of ​​Valaora.

The south-eastern fortification has been built in 3 phases. Judging by the construction techniques, the first phase is from the Hellenistic period, around the 4th century BC, the second phase is Roman or late Roman (maybe event early Byzantine) and the 3rd and last phase, whose stonework has many similarities with that of the medieval castle, is considered to be of the same era as the castle, i.e. late Byzantine.

The medieval castle, according to local tradition, was built by the Carlo Tocco, who at the beginning of the 15th century was the lord of the region having the title Count Palatine of Kefallinia-Zakynthos, Duke of Lefkada, and Baron of Vostitsa (Aigio).
He was a vassal of the kingdom of Naples and in his time had become the most powerful Frankish ruler in Greece. He extended his rule to other areas and among others he captured Chlemoutsi (in Kyllini), Megara and Corinth and finally, from 1411, he also became despot of Ioannina and Arta.

Nevertheless, we cannot be sure of the dating of the castle in the Tocco period because, apart from the oral tradition, there is no historical testimony nor has an excavation been carried out that would give more information. On the other hand, it is certain that the castle at Sivista was part of his territory and he probably repaired it as he did with many other castles in western Greece.
Various details of the construction, such as the towers which are open at the back, the absence of bricks from the stonework, some sloppiness in the construction, and the strange internal architecture are indications that the construction was done towards the end of the late Byzantine period, that is indeed the Tocco era, without excluding the possibility that the castle was built a little earlier, around the 14th century, by the Despots of Epirus.

Finally, we should mention something interesting about the south-eastern fortification. The medieval castle on top of the hill does not impress for the quality of its construction or for its architecture. But this does not apply to the south-eastern fortification whose 2nd construction phase, the late Roman, is unexpectedly of very good construction quality. The construction would require a group of skilled technicians and a large expense. It is not easy to understand why at that time it was deemed appropriate to undertake such an ambitious fortification project in an area that had always been isolated.

Sources