French Herbalist and Physician
Not only are the dates of Floridus Macer's life uncertain, even his identity has been a subject of dispute. One of the few things known about him, in fact, is that he wrote De viribus herbarum, which became one of the most widely consulted texts on herbal medicines during the late medieval and early Renaissance periods.
A great number of historians link the pseudonym "Floridus Macer"—or more often, simply Macer—with the twelfth century French physician and bishop, Odo of Meung or Maung. Others, however, assert that he was in fact Marbode, bishop of Rennes. From these competing views, it is at least possible to discern the barest of outlines to Macer's biography: that he was French, a cleric (itself not a surprise, since most learned men of medieval Europe were), and that he lived some time during the twelfth or perhaps the thirteenth century.
Macer's fame rests entirely on De viribus herbarum, or "On the powers of herbs." Written in Latin hexameter verse, the book discusses the medicinal qualities of various plants; for instance, Macer recommended savin, juniper, and spearmint as contraceptives. Heavily influenced by ancient thinkers, including Hippocrates (c. 460-c. 377 b.c.), Pliny the Elder (a.d. 23-79), Dioscorides (c. 40-c. 90), and Galen (c. 130-c. 200), the book is a mixture of science and superstition. Many of the cures recommended by Macer were derived by experimentation and observation; others are pure witchcraft or magic. In any case, the use of rhymes not only distinguished the Herbarum from other texts; it also made it easy to teach, and thus the book became a favorite of instructors and students alike.
It appears that the name "Macer" is a reference to Aemilius Macer, a Roman herbalist mentioned in the writings of the ancient poet Ovid. Initially scholars attributed the Herbarum to this author, but already in the first known manuscripts of the work (which date from the thirteenth century), the book is described thus: "Of the power of herbs, the author being Odo, called Macer of the Flowers."
With each edition of the Herbarum, errors made in copying became compounded, but by 1373 a more or less definitive edition appeared. In 1477, the Herbarum became one of the first books ever printed, and later versions contained ever more discrepancies Nonetheless, the book continued to be a standard medical text until the eve of the Enlightenment.