 The first took place on the "Cloostervelt" near Hondschoote, in what is now the arrondissement of Dunkirk in French Flanders, very close to where the attacks later began, and the first one to be armed against disruption was held near Boeschepe on July 12, 1562, two months after religious war had broken out again over the (then) French border just nearby.<ref>Petegree, 74–75</ref>

These open-air sermons, mostly by Anabaptist or Mennonite preachers, spread through the country, attracting huge crowds, though not necessarily of those leaning to Protestantism, and in many places immediately preceded the iconoclastic attacks of August 1566.Prosecutions for heresy continued, especially in the south, although they were erratic, and in some places clergy of clearly heretical views were appointed to churches.By 1565 the authorities seem to have realized that persecution was not the answer, and the level of prosecutions slackened, and the Protestants became increasingly confident in the open.<ref>Petegree, 82–86</ref> A letter of July 22, 1566, from local officials to the Regent, warned that "the scandalous pillage of churches, monasteries and abbeys" was imminent.<ref>Arnade, 97</ref>

On August 10, 1566, the feast-day of Saint Lawrence, at the end of the pilgrimage from Hondschoote to Steenvoorde, the chapel of the "Sint-Laurensklooster" was defaced by a crowd who invaded the building.