Johannes van Heeck, (Deventer 2 February 1579 – presumably Sant'Angelo Romano c.1620), (also known as Johann Heck, Joannes Eck, Johannes Heckius, Johannes Eckius and Giovanni Ecchio) was a Dutch physician, naturalist, alchemist and astrologer. Together with Prince Federico Cesi, Anastasio de Filiis and Francesco Stelluti, he was one of the four founding members of the Accademia dei Lincei, the first learned society dedicated to understanding of the natural world through scientific enquiry. Family background Johannes van Heeck was one of five children in a family of wealthy merchants. His father was Willem, son of Willem van Heeck, and his mother was Lutgardt, daughter of Gerrit. Between 1587 and 1591 his father, a Catholic, was one of Deventer's political leaders, elected senator and consul in 1589. For this reason, when Protestant forces under Maurice of Nassau took the city in 1591, Willem van Heeck was fined 150 guilders for being a leader of the Catholic party and a collaborator of the hated Philip II of Spain. Johannes received a humanist education, studying Latin, Greek, theology, astronomy and astrology, and making an exact observation of the comet that appeared in 1591, which he described in one of his later treatises as a bad omen for a life full of bitterness and pain. Under Calvinist rule, the position of his family became more precarious in Deventer and eventually his parents decided to send him to Italy to continue his education. Early career Van Heeck traveled to Milan, Parma, Ferrara, Venice, Bologna and Rome. He stayed for a while in Spoleto as a guest of Count Gelosi, with whom he maintained a connection throughout his life, and on whose estate was the villa known as the "museum deauratum" where many of his manuscripts were composed. Here he wrote works of a moral literary character, such as his 1596 Epigrammata, as well as medical, magical and astrological topics. Among these was his Liber de Regimine Sanitatis Eorum Qui Studio Litterarum Incumbunt in which, inspired by De Vita Libri Tres ('The Threefold Life') of Marsilio Ficino, he examined the hygiene, diet and amorous habits of the literati. The second part of the work dealt with Ficino's ideas on magic. He discussed the influence of images on the spirit, and the occult virtues of certain plants, approaching his enquiry from the medical point of view rather than from that of the magician. He concluded the treatise with