The Gvozdansko Castle was probably built in the second half of the 15th century, due to mining rights of Croatian Zrinski noble family. The castle was first mentioned in 1488. Nikola III Zrinski and his son Nikola Šubić Zrinski frequently came to Gvozdansko in order to inspect the mines and the mint.
The Turks attempted to conquer the Gvozdansko Castle on several occasions. Three major attempts were made in 1561 by Malkoč-beg, in 1574 by Ferhad-beg, and in 1576 by Kapidži-pasha. The final siege by Ferhat-paša Sokolović with 10,000 soldiers, which was fought from 3 October 1577 to 13 January 1578, was much better prepared. That Siege of Gvozdansko ended with an Ottoman victory, after long and bloody siege. Ottomans managed to break into castle only after last defenders froze to death in harsh winter, having no wood or anything else to light the fire, on 13 January 1578.
Ottoman rule in Gvozansko lasted until 1718. Ottoman commander was stunned by the brave Croatian defenders, after witnessing frozen bodies of defenders still holding their muskets on combat positions in the ruined castle.
References:The Broch of Gurness is an Iron Age broch village. Settlement here began sometime between 500 and 200 BC. At the centre of the settlement is a stone tower or broch, which once probably reached a height of around 10 metres. Its interior is divided into sections by upright slabs. The tower features two skins of drystone walls, with stone-floored galleries in between. These are accessed by steps. Stone ledges suggest that there was once an upper storey with a timber floor. The roof would have been thatched, surrounded by a wall walk linked by stairs to the ground floor. The broch features two hearths and a subterranean stone cistern with steps leading down into it. It is thought to have some religious significance, relating to an Iron Age cult of the underground.
The remains of the central tower are up to 3.6 metres high, and the stone walls are up to 4.1 metres thick.