The French naturalist and anatomist George Léopold Chrétien Frédérie Dagobert Cuvier (1769–1832) was the first to use a specific method to classify mammals. This method also established a system of zoological classification, dividing the animals into four categories based on their structures. His four categories were Vertebrata, Mollusca, Articulata, and Radiata. Cuvier is also considered by many to be the founder of comparative anatomy.