The Martyrs of Gorkum () were a group of 19 Dutch Catholic clerics, secular and religious, who were hanged on 9 July 1572 in the town of Brielle by militant Dutch Calvinists during the 16th-century religious wars—specifically, the Dutch Revolt against Spanish rule, which developed into the Eighty Years' War. Events In the first half of the 16th century, various forms of Protestantism—particularly, Lutheranism and Calvinism—were spreading through Western Europe. In the Low Countries, then under the rule of Spain, Emperor Charles V and his son King Philip II instituted a systematic campaign to root out the new religious movements, which resulted in political resentment towards the authorities, including the Catholic Church. Inhabitants of the northern Netherlands who were primarily Protestant began to turn against the Catholic priests and monastics present. By 1572 the Netherlands were in open revolt against Spanish rule, while in the internal rivalry among the Protestant denominations, Calvinism managed to suppress Lutheranism. On 1 April of the next year, Calvinist forces and a rebel group called the Watergeuzen (Sea Beggars) captured Brielle (Den Briel) and later Vlissingen (Flushing). In June, Dordrecht and Gorkum fell, and at the latter the rebels captured nine Franciscan priests: Nicholas Pieck, guardian of Gorkum; Hieronymus of Weert, vicar; Theodorus van der Eem of Amersfoort; Nicasius Janssen of Heeze; Willehad of Denmark; Godefried of Mervel; Antonius of Weert; Antonius of Hoornaer, and Franciscus de Roye of Brussels. To these were added two lay brothers from the same friary, Petrus of Assche and Cornelius of Wijk bij Duurstede. At almost the same time the Calvinists arrested the parish priest of Gorkum, Leonardus Vechel of 's-Hertogenbosch, and his assistant. Also imprisoned were Godefried van Duynsen of Gorkum, a priest in his native city, and Joannes Lenartz of Oisterwijk, a Canon Regular from a nearby priory and spiritual director for the monastery of Augustinian nuns in Gorkum. To these fifteen were later added four more companions: Joannes van Hoornaer (alias known as John of Cologne), a Dominican of the Cologne province and parish priest not far from Gorkum, who when apprised of the incarceration of the clergy of Gorkum hastened to the city in order to administer the sacraments to them and was seized and imprisoned with the rest; Jacobus Lacops of Oudenaar, a Norbertine, who became a curate in Monster, South Holland; Adrianus Janssen of Hilvarenbeek, a Premonstratensian canon and at one time parish