His son Johann VIII ("The Younger") returned in 1612 to the Roman Catholic Church, and also wanted to use force to make the townsfolk, too, convert back to Roman Catholicism. In 1632, Nassau-Siegen was conquered by the Swedes, after which his half-brother John Maurice of Nassau-Siegen, the Dutch commander in Brazil, re-introduced Protestantism. John VIII died in 1638 and was succeeded by his only son Johan Frans Desideratus, who had to cede part of Nassau-Siegen (north of the Sieg river) to the Protestant branch of the family.