The Catedrala Sfântul Nicolae stands directly opposite the Church with the Moon, two Orthodox churches sharing the same square — an indication of how central the Romanian community was to Oradea even under Hungarian rule. Built between 1800 and 1810 in a sober late-Baroque style, it serves as the cathedral of the Romanian Orthodox Diocese of Oradea.
The twin-towered façade is plain by Oradean standards, but the interior is worth a look for its iconostasis and the 19th-century wall paintings restored in the early 2000s. Services in the older Romanian liturgical tradition are held on Sunday mornings; visitors are welcome to slip in quietly at the back.