siðaskiptin

Siðaskiptin, or the Reformation, was a 16th-century religious, political, intellectual, and cultural upheaval that split the Western Christian Church into Catholic and Protestant branches. It began in 1517 when Martin Luther, a German monk and theologian, published his *Ninety-Five Theses*, criticizing the Catholic Church’s sale of indulgences and other practices. His actions sparked widespread debate and led to the formation of Protestantism, a movement that rejected several key Catholic doctrines, including papal authority, the authority of tradition, clerical celibacy, and the seven sacraments reduced to two (baptism and communion).

The Reformation was driven by a desire for religious reform, humanist scholarship, and the spread of printed literature, which allowed ideas to disseminate rapidly across Europe. Key figures included Huldrych Zwingli in Switzerland, John Calvin in Geneva, and Henry VIII of England, whose break with Rome in 1534 established the Church of England. The Counter-Reformation, the Catholic Church’s response, included the Council of Trent (1545–1563), which reaffirmed Catholic doctrine and initiated reforms to address abuses.

Siðaskiptin had profound social and political consequences, reshaping European society, governance, and culture. It intensified religious conflicts, such as the Thirty Years' War (1618–1648), and contributed to the decline of feudalism while fostering the rise of nation-states. The movement also influenced education, science, and the arts, laying groundwork for the Enlightenment. Its legacy persists in modern religious divisions, political structures, and cultural identities across Europe and beyond.