The Old Town of Ozalj is truly diverse from an architectural point of view. It was built and rebuilt in various eras, and each of them gave its own special characteristics to this extraordinarily valuable edifice.
Construction of the Old Town started sometime in the 6th century, which is confirmed by numerous remains of old Roman walls. However, the beginning of construction of today's edifice started in the 13th century. From 1244 it was owned by the King, then by different families: Babonić, Frankopan, Zrinski, Perlas, Batthyany and Thurn and Taxis who gave it to the current owners, "Brethren of the Croatian Dragon" society, in 1928. The Old Town is entered via a wooden bridge which was movable until 1821. The centre pillar which carries the bridge used to be a watchtower whose small openings for archers were used for defence of the town's trench. The pillar is also very interesting from an architectural point of view, since its lower part was built as a triangle, whereas its upper part as a square.
By crossing the bridge one enters the complex consisting of an entrance tower (built in 1599 by Juraj IV Zrinski), a smaller tower to the left of the entrance tower, and the main defensive-tower, i.e. Babonić tower (the oldest part of the complex), south, east and north wing (all three wings are big two-storey buildings) and Zrinski Palace which was home to many Zrinski generations. In the 18th century Ozalj was reconstructed and turned into a beautiful castle. R. Perlas thoroughly reconstructed the ruins of the Old Town, and Teodor Batthyany added the 2nd storey to the north wing and built a new baroque tract. The former Palace, long believed to be the oldest edifice of the existing complex, was turned into a grain warehouse, thus getting the name "Granary".
This historical building was home to Nikola, Petar and Katarina Zrinski as well as Frano Krsto Frankopan, strong figures whose characters and culture surpassed other Croatian and Austrian nobles.
The Zrinski Palace was built on a solid rock which ascends a slope over the Kupa River and has kept its authentic 16th-century architecture until the present days. It was constructed in a rectangular shape by Nikola Šubić Zrinski. The evidence thereof is the inscription engraved above the Palace entrance: NICO.CO.ZR.1556 (Nicolaus comes Zriniensis 1556 which means: Nikola Count Zrinski 1556).
On the ground floor of the Palace there is an antechamber and a bedroom with remnants of a fireplace and valuable wall frescoes of religious content, which is very rare in secular chambers of our feudal castles. The door then leads from the bedroom and antechamber to a bigger chamber which probably served as a living room. The walls here contain 16th and 17th-century Glagolitic and Latin inscriptions engraved with a sharp object, which also represents a unique and extraordinary phenomenon. On the first floor there is a large antechamber and only one big salon which was probably used for festivities. The assumption is that Nikola Šubić Zrinski Sigetski and his famous great-grandson, Viceroy Petar Zrinski had their wedding celebrations in this hall.
Even in those old days, masters of this town and celebrated heroes would sheath their swords and pick up their pens. According to Pavao Ritter Vitezović's notes, it was in Ozalj - probably in one of the Palace rooms- where Petar Zrinski wrote his epic poem “Adrianskog mora sirenu” (The Siren of the Adriatic Sea), a paraphrased translation from Hungarian into the Croatian language. And it is well known that Katarina Zrinska wrote her “Putni tovaruš“ (Traveling Companion) right here, at home, in Ozalj.Fran Krsto Frankopan probably wrote one of his lyrical poems for his collection "Gartlic za čas kratiti” (The Garden in which to Cheat Time) in the shade of fragrant jasmine or roses in Ozalj gardens.
Extravagant noblemen Thurn und Taxis had in their possession a large collection of castles. However, they were interested only in marvellous castles with amazing views, since an amazing view is just the detail which gives a castle its full beauty. For this reason they added the Old Town of Ozalj to their collection. Indeed, in the course of history, owners of the Old Town kept changing, but its wonderful view has remained until the present day.
The legend says that Katarina Zrinska jumped into the Kupa River from the Zrinski Palace when she heard about Petar's death; however the truth is that she was arrested in Graz in a Carmelite convent.
The Palace was home to Nikola Šubić Zrinski; it was also the venue of his wedding attended by many guests and which lasted for 7 days.
Additionally, there is a legend saying that beneath the Old Town of Ozalj there is a network of underground passages which could be used to leave the Town in case of any threat of danger. Allegedly, the passages were so big that a man on a horse could pass through them and come out several kilometres away from the Old Town.