The circle of Oporinus and Basel

Like many scholars, Wier wrote his works when the world was undergoing various profound changes, thanks to certain recent events (the discovery of the Americas and the Reformation) and innovative tools (printing). In such a revolutionary age, a strong challenge affected medical practice, that of Paracelsus. We cannot understand Johann Wier as a physician without studying the person who dominated sixteenth-century medicine, Paracelsus. Defending Galenism, Wier (who named one of his sons Galenus) had to tackle Paracelsism, but we can also find some important analogies between these two theories.

Renaissance humanism heralded a renewed interest in natural magic, and intensified the search for divine elements in the study of nature, spurred on by the revived and intense study of the Greek language and the rediscovery of the Corpus Hermeticum and other equally important works. In turn, medical and natural philosophical research ushered in two new directions of study: a renewed interest and development in traditional medicine, based on mathematics and physics, and a deeper understanding of chemistry, rooted in a mystic and religious understanding of nature. The consequences of the revolution in philology and the printing press spilled over into scientific and medical texts. In 1525, the first Greek edition of the works of Galen appeared, and, in the following year, an edition of the Hippocratic corpus. Both works contributed to the contemporary attack on Arabic science that was widely adopted during the High–Late Medieval Ages. This revolution was marked by the surprising coincidence, highlighted by Debus, of publication in the same year (1543) of Copernicus's De revolutionibus orbium coelestium (influenced by the translation of Ptolemy's Almagest), the De humani corporis fabrica of Vesalius, and the main Latin translation of the works of Archimedes.