Pseudo Isidore is the label given to an otherwise unknown author who referred to himself as Isidore Mercator*, writing in the 840s and 850s. The collection of 60 decretals from early popes include only two authentic ones. The two are placed first, in order to give the reader assurance that all were historical.
The point of these, also called the "False Decretals," was to give more authority to Frankish prelates. The Carolingian rulers, starting with Louis the Pious, were responsible for several episcopal trials, challenging the authority of the Church over the kings, and deposing bishops. The False Decretals attempt to create an historical foundation for the Church to have more rights and authority, to have autonomy for a bishop in his diocese, and provide immunity for bishops from trial and conviction.
One of the ways the forgery was discovered was Pseudo-Isidore's tendency to have the documents make reference to events that took place after the document at hand was supposedly written.
Pseudo-Isidore could not help slipping in some personal preferences outside of the attempt to give bishops more power. In a letter purported to be from Pope Clement, Isidore includes:
De castimoniae dico cautela, cuius species multae sunt. Sed primo, ut observet unusquisque, ne menstruatae mulieri misceatur, hoc enim exsecrabile ducit lex dei.
But first that anyone should make sure not to share company with a menstruating woman, for this is considered loathsome by the law of God.
This is entirely separate from the attempt to prove episcopal autonomy, and the author's personal concern is noteworthy. This got me thinking: what did the Middle Ages think about menstruation? Well, that's obviously a new topic for a new day. See you tomorrow.
*The name seems to be a blend of two known authorities: Isidore of Seville and Marius Mercator (c.390 - c.451), who wrote anti-Pelagian treatises and to whom St. Augustine wrote at least one letter.
