Søren Aabye Kierkegaard (5 May 1813 – 11 November 1855), a 19th century Danish philosopher and theologian, is generally recognized as the first existentialist philosopher. He bridged the gap that existed between Hegelian philosophy and what was to become Existentialism. Kierkegaard strongly criticised both the Hegelian philosophy of his time, and what he saw as the empty formalities of the Danish church. Much of his work deals with religious problems such as the nature of faith, the institution of the Christian Church, Christian ethics and theology, and the emotions and feelings of individuals when faced with existential choices. Kierkegaard's work resists definite interpretation, since he wrote most of his early work under various pseudonyms, and often these pseudo-authors would comment on and critique the works of his other pseudo-authors.