Protestantism represents the second largest strand of Christianity when taken as a whole, counting 593 million Protestants across the world. However, Protestantism is not a single church or communion but a diverse spectrum of independent communions and theologies, including Lutheranism, Methodism, Presbyterianism, and Anglicanism. Protestantism was born out of the Protestant Reformation (1517-1648), a movement against certain practices and teachings of the medieval and early modern Catholic Church led most notably by Martin Luther (1483-1546) and John Calvin (1509-1564). Three fundamental principles unify all strands of Protestantism: the doctrine of sola scriptura (“by scripture alone”) holds that the Bible alone is the sole judge and guide for any Christian faith and teaching; sola fide (“by faith alone”) teaches that the believer is justified only by his or her faith in Jesus Christ, not earned by good works, which are considered to be evidence of faith; and the doctrine of the universal priesthood of believers teaches that all Christians, not just ordained clergy, have the right and the duty to understand and interpret scripture.
The Protestant Reformation forever changed the face of Christianity as well as the course of Western history. The religious diversity created by the rise of Protestantism did much to shape modern religiopolitical principles like religious freedom and the separation of Church and State. Protestant values have also inspired much human rights advocacy, as demonstrated by Martin Luther King Jr. during the African-American Civil Rights Movement (1955-1968). The growth of secularism during the latter part of the twentieth century has led to a drop in Protestant numbers across Europe and North America, Protestantism’s historical strongholds. Conversely, Protestantism is on the rise throughout historically Catholic Latin America due to intense missionary efforts, particularly among Evangelical Christians.