Søren Aabye Kierkegaard (/ˈsɒrən ˈkɪərkəɡɑːrd/ SORR-ən KEER-kə-gard, US also /-ɡɔːr/ -gor; Danish: [ˈsɶːɐn ˈɔˀˌpyˀ ˈkʰiɐ̯kəˌkɒːˀ] ; 5 May 1813 – 11 November 1855) was a Danish theologian, philosopher, poet, social critic, and religious author who is widely considered to be the first existentialist philosopher. He wrote critical texts on organized religion, Christianity, morality, ethics, psychology, love, and the philosophy of religion, displaying a fondness for metaphor, irony, and parables. Much of his philosophical work deals with the issues of how one lives as a "single individual", highlighting the importance of authenticity, personal choice and commitment, and the duty to love. Kierkegaard prioritized concrete human reality over abstract thinking.
Kierkegaard's theological work focuses on Socratic Christian ethics, the institution of the Church, the differences among purely objective proofs of Christianity, the infinite qualitative distinction between man and God, and the individual's subjective relationship to the God-Man Jesus Christ, which came through faith. Much of his work deals with Christian love. He was extremely critical of the doctrine and practice of Christianity as a state-controlled religion (Caesaropapism) like the Church of Denmark. His psychological work explored the emotions and feelings of individuals when faced with life choices. Unlike Jean-Paul Sartre and the atheistic existentialism paradigm, Kierkegaard focused on Christian existentialism.