Pierre-Joseph Proudhon (; 15 January 1809 – 19 January 1865) was a French politician and the founder of mutualist philosophy. He was the first person to declare himself an anarchist and is widely regarded as one of the ideology's most influential theorists. Proudhon is even considered by many to be the "father of anarchism". He became a member of the French Parliament after the revolution of 1848, whereafter he referred to himself as a federalist.