Later on, in 1649, Count Petar Zrinski built, next to the old castle in the centre of Kraljevica on the peninsula at the entrance to the Bay of Bakar, completely new fortress and calls it „New Castle". The castle was built on the basis of the late Renaissance fortress, but with a lot of Baroque details. The builder of the castle is not known, but according to the economic and political connections of Count Petar Zrinski and a comparative morphological study, it can be assumed that the main builders were Venetians. The castle consists of a cellar, where storage rooms were located, the first floor and the second floor surrounding the beautiful atrium (the second floor was added later). Although the castle looks like a fortress from the outside, it was not built for this purpose (since a stronger fortress was not needed in this area) but it was built as a residence in its entire interior.

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It was very richly furnished and covered with black and white marble (only two mullions on the first floor and a magnificent black marble fireplace on the ground floor). The walls were decorated with gilded leather and many paintings and sculptures. In the atrium there are still visible parts of these glittering, magnificent Ionic capitals in the arcades of the floor, the entrance portal of the staircase leading to the second floor, and the baroque spit of the Zrinskih and Frankopan family, which was taken only there, and there the story begins the end of the short happy life of this castle. The national Croatian spirit, rising above narrow aristocratic interests and having the same difficulties with the Viennese court, has somewhat matured in the family (not in the modern sense, of course, because it was founded in the 19th century). The families begin to unite in their struggle for independence from the Austrian crown. Proof of this union is the marriage of Petar Zrinski to Ana Katarina, the sister of Fran Krsto Frankopan in 1641. This castle was built immediately afterwards and is an expression of a new climate in the relationship of the two. It is rumored that it was intended to be the capital of Croatia after the occupation of Vienna. This story is not confirmed, but it is the only reason for the construction of this castle in such a rich form next to the second one, which was built in the center of Kraljevica. But as wise and patient as Nikola Zrinski knew how to fight against Vienna, Petar Zrinski and Fran Krsto Frankopan were clumsy, and their conspiracy was discovered and fell into deceit in Austria in 1671.

After the death of Petar Zrinski, the castle was used as a dungeon, museum, military quarters for French soldiers, hospital for syphilis, cholera and typhus, jesuit theology and philosophy school with logic, dialectics, metaphysics, cosmology, psychology, ethics, Latin, Greek, Italian, Croatian, literature, mathematics, algebra, mathematics, algebra, geometry, mechanics, chemistry, physics and history, as a brothel for the Italian army, as military base for the German army, as military quarters for the Yugoslav army, as an emergency shelter for the homeless, as a warehouse for building materials, sawmills and carpentry workshops and as a rehabilitation center for paraplegics.