Liberal Christianity, also known as Liberal Theology and historically as Christian Modernism (see Catholic modernism and Fundamentalist–Modernist controversy), is a movement that interprets Christian teaching by taking into consideration modern knowledge, science and ethics. It emphasizes the importance of reason and experience over doctrinal authority. Liberal Christians view their theology as an alternative to both atheistic rationalism and theologies based on traditional interpretations of external authority, such as the Bible or sacred tradition. Liberal theology grew out of the Enlightenment's rationalism and Romanticism of the 18th and 19th centuries. By the late 19th and early 20th centuries, it was characterized by an acceptance of Darwinian evolution, a utilization of modern biblical criticism and participation in the Social Gospel movement. This was also the period when liberal theology was most dominant within the Protestant churches. Liberal theology's influence declined with the rise of neo-orthodoxy in the 1930s and with liberation theology in the 1960s. Catholic forms of liberal theology emerged in the late 19th century. By the 21st century, liberal Christianity had become an ecumenical tradition, including both Protestants and Catholics. In the context of theology, liberal does not refer to political liberalism, and it should be distinguished from progressive Christianity. Liberal Protestantism Liberal Protestantism developed in the 19th century out of a need to adapt Christianity to a modern intellectual context. With the acceptance of Charles Darwin's theory of natural selection, some traditional Christian beliefs, such as parts of the Genesis creation narrative, became difficult to defend. Unable to ground faith exclusively in an appeal to scripture or the person of Jesus Christ, liberals, according to theologian and intellectual historian Alister McGrath, "sought to anchor that faith in common human experience, and interpret it in ways that made sense within the modern worldview." Beginning in Germany, liberal theology was influenced by several strands of thought, including the Enlightenment's high view of human reason and Pietism's emphasis on religious experience and interdenominational tolerance. The sources of religious authority recognized by liberal Protestants differed from conservative Protestants. Traditional Protestants understood the Bible to be uniquely authoritative (sola scriptura); all doctrine, teaching and the church itself derive authority from it. A traditional Protestant could therefore affirm that "what Scripture says, God says." Liberal Christians rejected the doctrine of biblical inerrancy or infallibility, which they saw as the idolatry (fetishism) of the Bible. Instead, liberals sought to understand the Bible through modern biblical criticism,