Pope Stephen III
It is possible that the union of Charlemagne and Himiltrude was a Germanic form of marriage with fewer obligations than the sacramental marriage of the Church—what some medievalists have called "Friedelehe"—although the concept is controversial. Paul the Deacon writes in his "Gesta Episcoporum Mettensium" that Pepin was born "ante legale connubium" or "before legal marriage", but his precise meaning is unclear: he does not specify as to whether Charles and Himiltrude were not fully, legally married by the church, or if they simply got married after Pepin was born. In a letter to Charlemagne, Pope Stephen III described the relationship as a legitimate marriage, but he had a vested interest in preventing Charlemagne from taking a new wife—the daughter of the Lombard king Desiderius, who was a major political enemy of the papacy.