Baron Justus von Liebig (1803-73) was a scientist who pioneered the application of chemical theories to biology, creating the disciplines of biochemistry and organic chemistry and inventing modern fertilisers. As a Professor at the University of Giessen in Germany from 1826, he established the first laboratory to train students in chemical research, laying the groundwork for German pre-eminence in chemical science in the second half of the nineteenth century. He was highly regarded and an absolute authority in the subject, and other scientists regularly asked him to arbitrate in academic disputes.At the same time as Liebig's appointment as professor, the French artist David d'Angers (1788-1856) conceived the idea of a portrait pantheon of the heroes of the age. He stated that it was his task 'to give to posterity the features of distinguished men of our time' and travelled around Europe to find and record his subjects, making over 500 separate portraits. His belief in phrenology, a theory that stated one could 'read' character traits from a person's features, influenced d'Angers' decision to draw them from life. Combined with his strong convictions that art ought to be morally uplifting, the portraits are romantic, ideal images of the sitters. The large size reflects d'Angers' interest in Renaissance medals, which he saw as perfect examples of the power of medallions as witnesses to history.