The first known experts to consider aspects of body language were probably the ancient Greeks, notably Hippocrates and Aristotle, through their interest in human personality and behavior, and the Romans, notably Cicero, relating gestures to feelings and communications. Much of this early interest was in refining ideas about oration — speech-making — given its significance to leadership and government. Isolated studies of body language appeared in more recent times, for example Francis Bacon in Advancement of Learning, 1605, explored gestures as reflection or extension of spoken communications. John Bulwer's Natural History of the Hand, published in 1644, considered hand gestures. Gilbert Austin's Chironomia in 1806 looked at using gestures to improve speech-making. Charles Darwin in the late 1800s could be regarded as the earliest expert to have made serious scientific observation about body language, but there seems little substantial development of ideas for at least the next 150 years. Darwin's work pioneered much ethological thinking. Ethology began as the science of animal behavior. It became properly established during the early 1900s and increasingly extends to human behavior and social organization. Where ethology considers animal evolution and communications, it relates strongly to human body language. Ethologists have applied their findings to human behavior, including body language, reflecting the evolutionary origins of much human nonverbal communication. Austrian zoologist and 1973 Nobel Prize winner Konrad Lorenz (1903–89) was a founding figure in ethology. Desmond Morris, author of The Naked Ape, is an ethologist, as is the evolutionary biologist Richard Dawkins, a leading modern thinker in the field. Ethology, like psychology, is an over-arching science which continues to clarify the understanding of body language.