The great medieval canon lawyer Lyndwood illustrates the difficulty of distinguishing, even as late as the middle of the 15th century, between concubinage and a clandestine, though legal, marriage.
Gebhard is chiefly noted for his conversion to the reformed doctrines, and for his marriage with Agnes, countess of Mansfeld, which was connected with this step. After living in concubinage with Agnes he decided, perhaps under compulsion, to marry her, doubtless intending at the same time to resign his see.
The church endeavoured to make the wife of a first marriage the only true wife; but concubinage was known as an Irish institution until long after the Anglo-Norman invasion, and it is recognized in the Laws.
Next to these strictly lawful marriages came concubinage as a recognized legal status, so long as the two parties were not married and had no other concubines.
The bishop of Utrecht supported him warmly, and got him to preach against concubinage in the presence of the clergy assembled in synod.
The early Christians had naturally preferred the formless marriage of the Roman law as being free from all taint of pagan idolatry; and the ecclesiastical authorities recognized concubinage also.
Even as late as the Roman councils of 1052 and 1063, the suspension from communion of laymen who had a wife and a concubine at the same time implies that mere concubinage was tolerated.
Even Sir Thomas More, in his polemic against the Reformers, admitted that this concubinage was too often tolerated in Wales (English Works, ed.
And Francis of France in 1516; and the council of Trent, while insisting on far more stringent conditions for lawful marriage than those which had prevailed in the middle ages, imposed at last heavy ecclesiastical penalties on concubinage and appealed to the secular arm for help against contumacious offenders (Sessio xxiv.
As the middle ages drew to a close, earnest churchmen were compelled to ask themselves whether it would not be better to let the priests marry than to continue a system under which concubinage was even licensed in some districts.