The mysterious medieval fortress of Cudato above the Bilušića buk waterfall is the least well-known fortress along the Krka River, and the only one not mentioned by medieval sources.
The medieval fortress on the right bank of the Krka River in its upper course, erected on a prominent crest from which a view extends of Bilušića buk waterfall, which was first described by Grgur Urlić-Ivanović, was surveyed by the archaeologist Stjepan Gunjača, who noted the remains of walls. Gunjača considered that it was a smaller medieval fortification, for which he utilized the toponym “Grad” (town). The position of the fortress indicates that it monitored the crossing over the tufa barriers.
It is only possible to speculate about the period when the fortress was built, considering that it was not recorded in written sources, or had been noted under a different name. It can only be presumed that it was constructed at the same time as the other fortresses that composed the fortification system along the Krka River that originated from the time of the conflicts between the Šubić and Nelipić families.
The earliest evidence for its existence extends into the 16th century: on the map of Mateo Pagano from that time, it was recorded as the fortress of Cudato. It was again recorded centuries later, in Venetian cadastral records, under the names Castel Vechio and Torre Antica.