Did Northern Europe became largely Protestant?

Yes, Northern Europe did become largely Protestant.

The Protestant Reformation, a religious movement that began in the 16th century in Europe, led to the creation of new Protestant denominations and the separation of many Christian communities from the Catholic Church. The Reformation was particularly successful in Northern Europe, where several countries adopted Protestantism as their official religion, including Denmark, Sweden, Norway, Finland, and Iceland. The Reformation was also successful in parts of Germany, the Netherlands, and Switzerland, but it was not as successful in Southern Europe, where the Catholic Church remained the dominant religion.

There were a number of reasons why the Reformation was successful in Northern Europe. One reason was the political fragmentation of the region. In contrast to Southern Europe, where there were large, centralized states, Northern Europe was divided into smaller, more decentralized polities. This made it easier for religious reformers to spread their ideas and to establish new churches without facing strong opposition from the state.

Another reason why the Reformation was successful in Northern Europe was the region's strong intellectual and cultural traditions. Northern Europe had a long tradition of learning and scholarship, and this tradition was particularly strong in the areas of theology and religion. This made it more likely that people in Northern Europe would be receptive to new religious ideas.

Finally, the Reformation was also successful in Northern Europe because of the region's relatively high level of economic development. This economic development led to a growing sense of individualism and a desire for religious freedom, both of which were conducive to the spread of Protestantism.