Passing through the passageway of the Police Headquarters you reach the Cathedral dedicated to Saints Hilary and Tatian.

Behind the simple façade, rebuilt in 1924 after the destruction of the Great War, lies a very ancient place of worship, where precious works and testimonies of Gorizia's medieval history are still preserved.

The original nucleus of the cathedral certainly existed since the 14th century. Inside, in the presbytery, you can admire the high altar (1707) richly decorated with polychrome marble attributed to Giovanni Pacassi, the valuable 18th-century pulpit, and the large canvas (1820-21) by Giuseppe Tominz depicting the Virgin with Saints Hilary, Tatian, and Charles Borromeo, suspended above a small glimpse of the Gorizia panorama. At the end of the right nave is the 15th-century chapel of Sant'Acazio, the only room to have retained its 15th-century structure and decorations: noteworthy is the star-shaped vault with the symbols of the four evangelists. From here, a staircase leads to the crypt where the archbishops of Gorizia rest.

The left nave ends in the Chapel of the Santissimo, dating back to the 14th century, where you can admire the cenotaph of Leonardo, the last Count of Gorizia, along with other 16th-century tombstones.