At the start of the 16th century the southern Netherlands (more or less present-day Belgium) was part of the empire of the Spanish Habsburgs. On his accession to the throne in 1519, Charles V decided to create a State Inquisition, wrongly referred to as a "Spanish inquisition" as it was even more terrifying!
On 31 October 1517, Martin Luther, a German theologian, published his 95 theses which mainly considered one of the questions which he felt was key: the rising practice of the sale of indulgences by the Roman Catholic Church, authorised by Pope Leon X in order to finance the construction of Saint Peter's Basilica in Rome. Following this publication, several monks from the Augustinian monastery in Antwerp converted to Luther's doctrine. François Vander Hulst, the first Inquisitor appointed by Emperor Charles V and a member of the Council of Brabant, dealt with the affair by summoning the prior of the monastery, Jacques Praepositus. Once there, he was arrested and, after a few days in prison, he confessed and recanted at the Cathedral of St Michael and St Gudula in Brussels.
During the prior's imprisonment, the monks appointed Lambert Thoren as prior and continued to preach Luther's doctrine. The Inquisitor had them arrested. Unlike the other monks, Thoren, Voes and Van Eschen refused to recant. They were tried at Grand Place in Brussels on 1 July 1523. Thoren asked for a further period of reflection. That afternoon, Voes and Van Eschen were burned at the stake on Grand Place.
Henri Voes and Jean Van Eschen were the first Protestant martyrs.