The Marburg School is a term used to describe a group of Neo-Kantian philosophers at the University of Marburg in the second half of the 19th century and early part of the 20th century. The New Criticism, as neo-Kantianism was also called, was sceptical of 19th-century materialism and naturalism. Friedrich Albert Lange (1828–1875) called for a return to Kant and his distinction between aprioristic and empirical knowledge. The classical Kantian metaphysical realism (‘thing in itself’) was nevertheless rejected in the Kantian renaissance. The key figures of the new critical and transcendental idealism at its zenith were Hermann Cohen (1842–1918) and Paul Natorp (1854–1924).