Norwegian Christianity was a project of the crown, and its founding figure lost. Olaf Haraldsson was killed at Stiklestad in 1030 fighting an alliance of Norwegian magnates who did not want him or his religion, and within a year of the battle he was being venerated as a saint. That reversal is the whole shape of the thing: a king who lost his war became Rex Perpetuus Norvegiae, the eternal king of Norway, and his shrine at Nidaros became the seat of an archbishopric whose province covered Iceland, Greenland, the Faroes, Orkney, Shetland and the Isle of Man. Pilgrims walked to Trondheim from across the North Atlantic for four centuries.
The Reformation reversed the direction of travel. It arrived in 1537 by decree from Copenhagen, the shrine was stripped, the relics disappeared and the pilgrim roads went out of use. What replaced the shrine was a state church of unusual reach, which registered births, ran the parish schools and, from the eighteenth century, required confirmation before a young person could marry or take up a trade.
Separation came slowly and recently. The constitution was amended in 2012 to remove the Evangelical Lutheran faith as the official religion of the state, and the Church of Norway became a legally independent body in 2017, taking over its own employment of clergy. The financial arrangement that survived is the more interesting inheritance: the state funds the Church of Norway and pays every other registered religious and life stance community an equivalent grant per registered member, so the Humanist Association is funded on the same head count basis as a diocese.
Sources From Viking Stronghold to Christian Kingdom: State Formation in Norway, c. 900-1350Sverre Bagge with The Early Reformation in Denmark and Norway 1520-1559 (in The Scandinavian Reformation, ed. Grell)Martin Schwarz Lausten, in Ole Peter Grell (ed.), A Legitimate Church Democracy? Legitimacy Work and Democratic Reform during the Separation of Church and State in NorwayHelge Nylenna and Stephen Sirris, Norway: State and Church Separate After 500 Years (Global Legal Monitor)Law Library of Congress staff