Medieval philosophy (5th – 16th century) is the period following the fall of the Western Roman Empire and was dominated by the rise of Christianity and hence reflects Judeo-Christian theological concerns as well as retaining a continuity with Greco-Roman thought. Problems such as the existence and nature of God, the nature of faith and reason, metaphysics, the problem of evil were discussed in this period. Some key Medieval thinkers include St. Augustine, Thomas Aquinas, Boethius, Anselm and Roger Bacon. Philosophy for these thinkers was viewed as an aid to Theology (ancilla theologiae) and hence they sought to align their philosophy with their interpretation of sacred scripture. This period saw the development of Scholasticism, a text critical method developed in medieval universities based on close reading and disputation on key texts. The Renaissance period saw increasing focus on classic Greco-Roman thought and on a robust Humanism. Early modern philosophy in the Western world begins with thinkers such as Thomas Hobbes and René Descartes (1596–1650).[36] Following the rise of natural science, Modern philosophy was concerned with developing a secular and rational foundation for knowledge and moved away from traditional structures of authority such as religion, scholastic thought and the Church. Major modern philosophers include Spinoza, Leibniz, Locke, Berkeley, Hume, and Kant.[37][38][39] 19th-century philosophy is influenced by the wider movement termed the Enlightenment, and includes figures such as Hegel a key figure in German idealism, Kierkegaard who developed the foundations for existentialism, Nietzsche a famed anti-Christian, John Stuart Mill who promoted Utilitarianism, Karl Marx who developed the foundations for Communism and the American William James. The 20th century saw the split between Analytic philosophy and Continental philosophy, as well as philosophical trends such as Phenomenology, Existentialism, Logical Positivism, Pragmatism and the Linguistic turn.