Coins showing the heads of Roman emperors. Illustration from an 18th century edition of 'Historiae naturalis' (Natural History) by Pliny the Elder (23-79 AD), published in Paris in 1723. The 1469 edition was the first important printed book in science, and encyclopedia of many subjects, revered for over fifteen centuries. It was claimed to be one of the most influential books ever published.
© Science Museum / Science & Society Picture Library