_Hieronymus Mercurialis_ (1530-1606), a famous physician, and widely known throughout Europe on account of his medical writings, while he was still a young man, in the household of Cardinal Alexander Farnese at Rome, began his literary career with a treatise on the gymnastics of the ancients (_De arte gymnastica_)[6]—a book which seems to have enjoyed a remarkable degree of popularity and is often cited by more recent writers. It was first published at Venice in 1569, but at least three more editions appeared in Venice and one in Paris during his lifetime, and others after his death, including one in Amsterdam as late as 1672. Out of his rich store of classical learning—the first edition contains a list of ninety-six Greek and Latin authors upon whom he has drawn—Mercurialis seeks to reproduce for his readers the ancient gymnasia and gymnastic exercises; but in the second half of the volume he leaves the descriptive and historical and turns to the hygienic and medical aspects of exercise, as viewed from the critical standpoint of the physician. Somewhat like Cardano, he first considers the value of exercise in conditions of health and disease and the general principles that govern its application, and then takes up the nature and effects of particular exercises in some detail. According to the title page the work was not intended for the use of physicians only, but for all who were interested in the study of archeology or in the preservation of health.[7] In Germany _Martin Luther_ (1483-1546) realized the recreative and moral value of bodily exercise, and recommends especially such knightly sports as fencing and wrestling. The Swiss reformer _Ulrich Zwingli_ (1484-1531), writing on the subject of education in 1524, makes suggestions regarding diet and clothing, and refers to running, jumping, hurling stones, wrestling, and fencing as a means of acquiring strength and skill. He also considers wrestling and fencing a useful preparation for military service. _Joachim Camerarius_ (1500-1574), who taught in Nuremberg, Tübingen, and the University of Leipsic, and was the friend and biographer of Melanchthon, published in 1544 a brief dialogue on bodily exercise (_Dialogus de gymnasiis_).[8] The author believes that boys should be encouraged to run, jump, wrestle, fence, and play ball outdoors, and one of the speakers, after mentioning the gymnastics of the ancients and the performances of the old Germans, describes to his companion a model school for the common people in which the teacher provides for indoor practice in hanging from a bar, climbing a rope, lifting weights, and matching strength with an opponent in various ways, and for a number of active games in the open air, some of them described in the text. Among the most illustrious names in the history of educational reform is that of _Johann Amos Comenius_ (1592-1671), a Moravian pastor and teacher who suffered persecution and banishment in the course of the Thirty Years’ War.