The fortress of New Castle as the main defense citadel against the Turks was the part of the main fortification of Banská Štiavnica together with other buildings.
New Castle had also the function of a watch tower. It was the part of military signaling equipment against the Turks on the territory from Levice to Ľubietová called Central Slovak Mining Towns Association (7 known mining towns – Pukanec, Nová Baňa, Banská Štiavnica, Banská Belá, Kremnica, Banská Bystrica and Ľubietová).
The draftsman of the fortress was Pietro Ferrabosco, an Italian architect in Vienna court’s service. His works were known not only in the region of mining towns but in Central Europe, too. The name of the fortress is the result of the fact that in Banská Štiavnica was an older castle, too. The former parish church was rebuilt to a fortress against the Turks (Old Castle) in 1546-1559, so the new fortress got the name New Castle.
New Castle was opened to the public as a museum in 1971; the permanent exhibition is located on the 4 floors.