The castle was built as a three-story fortress, each level serving a distinct purpose. The ground floor, portions of which still stand, functioned as a temple. Its position level with the hillside made it accessible to the public, and the religious artifacts found there confirm its sacred role. Twenty-one stone steps connected the levels. Stone foundations supported the stairways and columns, while the walls themselves were built of sun-dried adobe bricks. The second floor was residential, constructed on a triangular stone bench to accommodate the slope of the mountain. Its rooms were interconnected and painted in blue, cream, black, and brick red. Bronze arrowheads and archery equipment found on this level suggest it housed the garrison and military stores. The third floor, known as the ruler's residence, contained wide rooms with large doors and windows, supported by twelve stone capitals and columns of both stone and wood. French archaeologist Andre Godard documented a hall with a table and chairs decorated in bronze.

The castle's earliest known inhabitants were the Mannaeans, a people who occupied the region south of Lake Urmia during the early first millennium BC until Assyrian invasions disrupted their hold. The Medes, who would go on to help destroy the Assyrian Empire in 612 BC, subsequently made Ziwiyeh their stronghold. The Scythians, nomadic warriors who swept south from the Eurasian steppe, also used the castle. This succession of occupants transformed Ziwiyeh into a layered archaeological record. Artifacts found at the site date to the 9th century BC and span the Mannean, Median, and Scythian periods. Among the most famous is a large golden necklace engraved with mythical animals, a piece that blends the artistic traditions of all three cultures. Iran's Cultural Heritage Organization has partially restored sections of the site.

The castle's builders understood both beauty and survival. Two gates, one on the north face and one on the south, controlled access. The southern gate, positioned on the side of the mountain peak, was decorated with ornamental tilework. The floors throughout the building were paved with brick or tile. Most remarkably, the fortress had a water piping system drawing from springs in the neighboring mountains, ensuring the garrison could endure a prolonged siege. The third floor's barn stored provisions for just such emergencies. This combination of practical engineering and decorative refinement distinguishes Ziwiyeh from cruder mountain fortifications of the period. It was built not merely to resist attack but to project authority.

In 1947, the fields outside the castle walls yielded the Ziwiye hoard: a collection of gold, silver, and ivory objects that would eventually scatter across the world's great museums. Gold rhytons, necklaces, plaques, and bracelets displayed an extraordinary fusion of Scythian animal style, Assyrian formality, and local Median craftsmanship. The treasure's discovery catapulted Ziwiyeh from regional obscurity to international fame, though it also invited controversy over provenance and authenticity. Today the castle itself, partly rebuilt by Iranian conservation efforts, stands as the quieter half of the Ziwiyeh story. The treasure travels the world in museum cases. The mountain, the cave, and the stone foundations remain where the Mannaeans placed them.