Final answer:
The Protestant Reformation, a significant religious movement that reshaped Christianity in Europe, was initiated by Martin Luther in the 16th century in Germany.
Step-by-step explanation:
The 16th century movement originating in Germany and initiated by Martin Luther was known as the Protestant Reformation. Martin Luther, a German monk and professor of theology, sparked this movement in 1517 by posting his '95 Theses' on the door of the Castle Church in Wittenberg. These theses criticized various practices of the medieval Roman Catholic Church, particularly the sale of indulgences, and advocated for reform within the Church. Luther's call for spiritual transformation and adherence to scripture as the sole source of Christian authority led to a major shift in European Christianity, with the emergence of Protestantism as a distinct branch separate from Catholicism.