The Reformation in Leiden began soon after news of Luther's 1517 protest against the sale of indulgences reached the city. In the midst of active Roman Catholic piety, which created a market for hundreds of copies of devotional manuals produced by the printing presses of Huych Jansz. van Woerden and Jan Zevertsz., new, Lutheran ideas made their appearance. Jan Zevertsz. printed Lutheran books as early as 1519. He also marketted them in the Antwerp fairs. Lutheran books were forbidden in Leiden in 1521. Within a few years Jan Zevertsz. was hauled to court to answer for what had become a capital offense. The Catholic pastor at Woerden, on the eastern border of the county of Holland, was openly Lutheran, and a small group of adherents of the new ideas could be found in Leiden as well. Developing a particular Dutch version of the Reformation, with less emphasis on the sacraments than remained in Lutheranism but without taking on Calvinist views, they became known as Sacramentarians.

Anabaptists rejected Catholic sacraments entirely, including infant baptism. The first Anabaptist martyr from Leiden was Marytgen Davidsdr., who in 1528 was drowned at Alkmaar as punishment for being rebaptized. In the 1530's Anabaptist uprisings led to the capture of Amsterdam's city hall, and the longer capture of the entire city of Münster in Germany, but a plot to take over the town of Leiden was discovered and foiled. Jan Beuckelsz. from Leiden ("Jan van Leyden") and his followers in Münster were vanquished and executed; their supporters were harried and persecuted throughout the Low Countries. Given hope and a loose form of organization in independent congregations by the Frisian former priest Menno Simons, the remnants became pacifists known as Mennonites. They were abhorred by Catholics, Lutherans, and Calvinists for their rejection of infant baptism and other doctrines retained by the others, as well as because of the suspicion that they were secret revolutionaries still waiting for a chance to grab for power. Leiden's place of execution, the Gravensteen just north of the Pieterskerk, saw the judicial murders of many Mennonites, including Adriaen Vermeer, the father of the later burgomaster Pieter Adriaensz. van der Werff . There was nothing distant about the Spanish Inquisition.

By the second half of the 16th century, the majority of Reformation supporters in Holland gradually became followers of the French Reformer active in Geneva, Jean Calvin. One of their leaders was Petrus Bloccius, a teacher in Leiden's Latin School across the square from the place of execution. The Reformed achieved permission to hold services in 1567, and the city became officially Reformed in 1572. The Lutheran and Mennonite congregations continued to exist, swelled in numbers by refugees from regions in the line of battle during the religious wars in Germany, France, and Belgium. As dissenters from the Calvinist majority, eventually rigid in its definition of orthodoxy, the Lutherans and Mennonites were joined by the Remonstrants, who were ejected from the Reformed Church at the Synod of Dordt in 1619. The Remonstrants were a group of clergy and influential laymen who had protested against increasing narrowness within the Reformed church, and whose support of the ideas of Professor Jacobus Arminius and his successor Simon Episcopius represented the continuation of the more liberal Netherlandish tradition arising out of the Sacramentarian movement, informed by but not dominated by the strict ideas of some others among Calvin's students.

More on the Reformation in Leiden:

L. Knappert, De Opkomst van het Protestantisme in eene Noord-Nederlandsche Stad, Geschiedenis van de Hervorming binnen Leiden (Leiden: S. C. van Doesburgh, 1908).

J. D. Bangs, "Further Adventures of Jan Zevertsz., bookprinter and parchmentmaker of Leiden," Quaerendo, A Quarterly Journal from the Low Countries devoted to Manuscripts and Printed Books, 7 (1977), 128 - 143;- "Reconsidering Lutheran Book Trade: the so-called 'Winkelkasboek' of Pieter Claesz. van Balen," Quaerendo, 9 (1979), 227 - 260.

C. O. Bangs, Arminius, A Study in the Dutch Reformation (Nashville: Abingdon Press, 1971;Grand Rapids: Francis Asbury Press, 1985 (2nd ed.)