Located above the Village of Podcetin, Croatia - it's initial date of construction is unknown. It has been speculated that Cetin may have been a Roman Era hill fortification or watchtower. Built on a plateau hill, Cetin Castle has a commanding view of the valley below. Much of the structure is today - in ruins. From it's initial appearance, it had an outer perimeter defensive wall (possibly a curtain type), built into the hill as a form of additional defense and strength.
There is evidence (foundations), of other interior structures that may have been inside as well. The remains of a Keep are still present. Cetin also has evidence of several defensive Towers (facing the valley). Several monasteries were built nearby (to use the protection from the castle garrison). Cetin came under control of King Sigismund (Holy Roman Emperor), who gave it to local Nobility (for services rendered to him at The Battle of Krbava Field in 1493).
After the defeat of Hungarian forces (of which Croatia was a Vassal State), at The Battle of Mohac - local Government collapsed. Due to the death of King Louis II of Hungary - Cetin was used by the "first" Parliament of Croatia to elect The Archduke of Austria as ruler. Serving as a bastion in the Croatian frontier, Cetin was important as a "check" to The Ottoman Empire.
The Turks took control of the castle many times (mostly involving great damage to the structure). In 1790, Austrian forces took Cetin back, but within the month - The Turks besieged it and took it back from Austria! Holding it until 1809, The Illyrian Provinces threatened war - and they released it. The castle was slighted by The Turks prior to their departure. Whatever stone was left, was stripped for use by the local population. The ruins of Cetin can be visited.