The study of animal behaviour, which had been going on in an anecdotal way since Aristotle, had its roots in natural history. It became more scientific during the 19th century. The French zoologist Étienne Geoffroy Saint-Hilaire was the founder of ethology in Europe, and his son Isidore produced a three-volume encyclopaedia "Histoire Naturelle Générale". In the third volume he talked about animal behaviour in almost modern terms. The entomologist J.-H Fabre (1823–1915) was a remarkable observer of natural life. His popular writing on natural history kept ethology alive in Europe.