Founder of a lay confraternity in the city of Roskilde in Denmark formed around 1150 in order to fight against the heathen Wends.
Wetheman probably belonged to the Danish aristocracy; he was one of the leading figures in the crusades organized in the Baltic region by King Valdemar I of Denmark and Absalon, bishop of Roskilde (1158-1178) and later archbishop of Lund (1178-1201). Wetheman and his confraternity are known only from the chronicle of Saxo Grammaticus (written around 1200), which seems to give a paraphrase of the statutes of the confraternity from a now lost written source.
All of the members of the confraternity were equal. If they lacked funds, the citizens of Roskilde could share their expenses in return for half of the booty, and the confraternity had the right to take a man’s ship, without his approval, in return for an eighth of the booty. Contrary to usual practice and customary law in the area, Christian captives discovered among the Wends were to be given clothes and sent back to their homes. Before battle, the members confessed their sins as if they were on the threshold of death. The ascetic behavior on campaign expected by the statutes gave the wars of the confraternity an almost penitential character, which, taken together with the other religious and charitable elements, places them within the general context of crusading ideology.
Early twelfth-century parallels to this organization are known from Spain, for example, the confraternities of Belchite and Monreal.