The Puppet State Era in Norway began in 1537, following a turbulent period of war and religious conflict. Norway had been part of the Kalmar Union since 1397, alongside Denmark and Sweden, but this union disintegrated over time. Sweden permanently left in 1523, leaving Denmark and Norway tied under Danish rule. However, tensions rose as the Protestant Reformation took hold in Denmark, while Norway remained largely Catholic.
When King Frederick I of Denmark initially promised not to impose Protestantism on Norway, this agreement was short-lived. Archbishop Olav Engelbrektsson of Trondheim led the Norwegian resistance against Protestant reforms and even invited Christian II, the deposed king, to return from exile. Christian II’s attempt to regain power failed, and Frederick's son, Christian III, ascended to the throne after a bloody succession struggle.
In 1537, Christian III invaded Norway, officially annexing it into Denmark. Norway was stripped of its status as an independent kingdom and became a puppet state under Danish control. Christian III dissolved Norway’s Council of State, seized church property, and imposed the Protestant Reformation. The Norwegian Church, a key institution and symbol of national identity, was dismantled, and its wealth flowed to Denmark. The shift also introduced Danish as the written language of government, further eroding Norwegian autonomy.
This era saw the rise of a centralized, professional administration controlled directly by the Danish monarchy. Local nobility lost influence, and officials appointed by the king began to govern Norway. While Norway retained its own distinct dialects, it no longer functioned as an independent entity, instead becoming a subordinate province of Denmark. The appointment of a Danish viceroy based at Akershus Fortress in Oslo underscored Norway’s reduced political status.