There are a number of places called Ovriocastro or Evraiocastro in Greece, the term meaning Hebrew Castle. These castles or fortresses were mostly built by various wealthy Western Europeans (the one in the photo by the Gattelusi family from Genoa in the 14th-15th century) on land which they were given by the Byzantine Emperor "in return for services rendered". So one theory for the name is that they were used by the Jews as a place of refuge when the Ottomans took over, another is that the Ottomans used the term Jewish to refer generally to the previous occupants. There's not much left of this particular one but the location is very beautiful.