St. Michael's Cathedral is a Roman Catholic church built in the 13th century and one of the most important Gothic buildings in Transylvania. It stands inside the Alba Carolina Citadel, immediately adjacent to the Orthodox Coronation Cathedral — the two churches together forming a striking visual emblem of the region's layered religious history. The cathedral has been rebuilt, modified, and restored many times over the centuries, but its basic Gothic structure survives.
Inside you will find Romanesque and Gothic architecture side by side, as well as the tombs of several significant historical figures including John Hunyadi and the voivode Iancu de Hunedoara. The archdiocese of Alba Iulia is still administered from here, and the cathedral remains an active place of worship. The cloister and adjacent bishop's palace are worth exploring alongside the main building.