On our last morning in Oslo, we visited the cathedral. Seems like it had been closed when we tried to go before. It was consecrated in 1697 and restored to its original baroque interior in 1950. Oslo Cathedral is the main church for the Church or Norway, Diocese of Oslo, as well as the parish church for downtown.
Thanks to Lynn, this is the coat of arms of Hallvard, patron saint of Oslo.
Last piece of ceiling art, posted earlier: