Demetrius Zvonimir (Croatian: Dmitar Zvonimir, pronounced [dmîtar zʋônimiːr], Latin: Demetrius Suinnimir/Zuonimir/Sunimirio, died 20 April 1089i[›]) was King of Croatia and Dalmatia from 1075 until his death in 1089. He was crowned as king in Solin on 8 October 1076. Zvonimir also ruled as Ban of Slavonia (1064–1074), and was named Duke of Croatia in around 1075. His native name was Zvonimir; he adopted the forename Demetrius (Dmitar in Croatian) at his coronation.

He began as Ban of Slavonia in the service of King Peter Krešimir IV. Afterwards, he was appointed as Duke of Croatia by Peter Krešimir IV, who later declared him as his heir. In 1075, Demetrius Zvonimir succeeded to the Croatian throne through papal diplomacy. His reign is characterized as relatively peaceful, with no extensive war campaigns; he focused instead on Croatia's economic and cultural development. He was the last native king who exerted any real power over the entire Croatian state, 

which he inherited at its height and ruled from the city of Knin.

Medieval legends allege his assassination; his death and succession are subjects of controversy in Croatian historiography. His reign was followed by a period of anarchy. Most sources describe him as Croatia's last native king 

King Zvonimir , had donated to a Benedictine from Split possession in the Kaštela field (Kaštelansko polje) in 1078. 

In the 12th century Benedictines built a church of St. Cosmas and Damian in the Romanesque Architecture style.

After the fall of Klis, following the peace treaty between Venice and the Ottomans, only a small coastal area remained under Venetian rule. 

To protect against the Turkish threat, Benedictine nuns completed the construction of the fortified settlement Kaštilac on the islet of Gomilica in 1545.

For the construction lime stone was used from the roman ruines of Salona 

Entrance to the castle is protected by a high tower over the stone bridge with arches. Kaštilac castle is 40 metres (130 ft) away from the shore, Connected with the stone bridge. The Fortress has a square floor plan and in the past, at the entrance was located a drawbridge. 

Kozica coat of arms

After the fortress was completed inhabitants of the Upper and Lower Kozica settled within the walls, after the Turks had devastated their former villages. 

Ottoman sword

Kastilac is one of the remaining 7 castles that succesfully protected against the turkish threat

The entrance to the fortress is still protected by a tall tower that could be reached through a movable wooden bridge. In addition to the nuns, the castle was inhabited after 1532 by the villagers of Kosica, whose houses were destroyed by the Turks, and when there were no other places, the farmers settled in its surroundings. 

In the 17th century the tower lost its defensive function. 

Today the fortress serves as one of europe's favourite film locations and has been used for game of thrones.

It provided the scenery for the city of Braavos and has been nominated as europe's best film location