Saint Ansgar's Cathedral (Danish: Sankt Ansgars Kirke — Katolsk Domkirke) in Copenhagen, Denmark, is the principal church of the Roman Catholic Diocese of Copenhagen, which encompasses all of Denmark, including the Faroe Islands and Greenland.

Starting with the one formed by the Spanish diplomat (and poet) Count Bernardino de Rebolledo, who served in Denmark between 1648 and 1659, continuous church registers were kept.

For some time the Austrian legation had been the main supporter of the congregation, and the new chapel was financed by Empress Maria Theresia.

During 1988–1992 the church underwent extensive restoration in collaboration with the National Museum of Denmark under the direction of the architect Vilhelm Wohlert.

[1] However, the Aarhus University radiocarbon-dated the skull to 340–431 AD,[3] eliminating the possibility of belonging to Lucius, who died in 254.