The medieval castle that surrounds the settlement ofwas created by the first Franks settlers of the island, in the 13th century. After the conquest of Constantinople, by the Crusaders, in 1204, Syros came under the domination of Western, who chose the point that is built Ano Syros till today to build their city.
Already, the village has a natural fortification because of its location, but as Syros, like all the coastal areas at that time were mainly threatened by the piracy, was built the medieval castle surrounded the village.
Today, the traces of the medieval castle of Ano Syros are visible in the modern settlement that in any case keeps unchanged the medieval character: first of all, the three gates of the medieval castle, which until today are the main entrances to Ano Syros. Parts of a medieval castle can be seen by a visitor in the village.
The medieval castle of Ano Syros maintains the air of another period, in one of the most beautiful parts of the island that worth a visit by anyone.