The true identity of the monster was decided correctly by the French anatomist Georges Cuvier. In 1795 French troops were outside Maastricht, and Cuvier arranged for the large skull to be saved when they stormed the town. The skull duly went to Cuvier in Paris, because he was the leading comparative anatomist of the day. He recognized the skull as that of a giant lizard, from its teeth and skull bones, though not until 1808, and by then the son of a Dutch professor, Adriaan Camper, had already had the same idea. The discovery of the specimen was important in another way, because it helped to convince Cuvier that extinction of some species was a fact. Cuvier later came up with a catastrophism-type theory.