Existentialism is a philosophical approach to understanding human existence and experiences. It is based on the assumption that individuals are free and responsible for their own choices and actions. Hence, we are not victims of circumstance because we are what we have chosen to be. Most of its thinkers came out of continental Europe. The roots of existentialism started with the so called "Father of Existentialism", Søren Kierkegaard, who lived in the 19th Century. Existentialism's peak came in the 1940's with great thinkers such as Sartre, de Beauvoir, Camus and Merleau-Ponty all coming out with not only traditional philosophical essays, but also plays, novels, and short stories that all reflected the existential school of thought. While this timeline doesn't cover every existentialist and their work, it does focus on the most important and most influential existential philosophers and their primary existential works.