The doctrines of the Reformation had early obtained a footing in various parts of the Netherlands. At first it was the teaching of Luther and of Zwingli which gained adherents. Somewhat later the Anabaptist movement made great headway in Holland and Friesland, especially in Amsterdam. The chief leaders of the Anabaptists were natives of Holland, including the famous or infamous John of Leyden, who with some thousands of these fanatical sectaries perished at Münster in 1535. Between 1537 and 1543 a more moderate form of Anabaptist teaching made rapid progress through the preaching of a certain Menno Simonszoon. The followers of this man were called Mennonites. Meanwhile Lutheranism and Zwinglianism were in many parts of the country being supplanted by the sterner doctrines of Calvin. All these movements were viewed by the emperor with growing anxiety and detestation. Whatever compromises with the Reformation he might be compelled to make in Germany, he was determined to extirpate heresy from his hereditary dominions. He issued a strong placard soon after the diet of Worms in 1521 condemning Luther and his opinions and forbidding the printing or sale of any of the reformer's writings; and between that date and 1555 a dozen other edicts and placards were issued of increasing stringency. The most severe was the so-called "blood-placard" of 1550. This enacted the sentence of death against all convicted of heresy--the men to be executed with the sword and the women buried alive; in cases of obstinacy both men and women were to be burnt. Terribly harsh as were these edicts, it is doubtful whether the number of those who Suffered the extreme penalty has not been greatly exaggerated by partisan writers. Of the thousands who perished, by far the greater part were Anabaptists; and these met their fate rather as enemies of the state and of society, than as heretics. They were political as well as religious anarchists.