A protestant friend of mine recently approached me regarding his interest in the Catholic church. His most recent question regarded prostitution (see below) I have good basic understanding of Catholic teaching but this was a curve ball Prior to this statement (see below) I was telling him about the authority needed to understand scripture and the historical teaching of faith/morals of the Church are without error for 2000 years. Thank you for any response you can provide.
(email I received from protestant friend)
I, briefly, surfed the internet to find out about “medieval prostitution” – here’s what I found. I didn’t have time to completely verify that this information is NOT coming from a cuckoo source. I just typed in a few things and it pulled up a lot of information. Here are a few of the things I found:
Ruth Karras, author of Common Women: prostitution and sexuality in medieval England, discusses how some bishops ran and owned brothels in England during the fifteenth and sixteenth centuries. “Ecclesiastical institutions and individuals owned brothels . . . Several individual clerics also managed brothels in London and Westminster.”  She mentions also that they were not only owners, but many were clients as well.  Karras is not the only one to show that the clergy were clients of prostitutes. “. . . in the cases of procuration and brawling in the brothel or the bathhouse, members of the clergy are listed as present, named and given as residents of the city . . . clergy still made up twenty per cent of the clientele of the bathhouses and the private bordellos of Dijon.” 
Not only was the Church involved in ownership, but in France during the mid thirteenth century, they accepted alms from prostitutes.  “In accepting the prostitute’s alms, the Church recognized that she had acted out of necessity.”  The Church supported this institution because they believed it to be a necessity. They owned and ran brothels, accepted money from prostitutes, and used Mary Magdalene as an example of a prostitute who redeemed herself by repenting. Many were tolerant of prostitutes by acknowledging them as a future Mary Magdalene. 
The church followed the philosophy regarding prostitution as a “necessary evil” and often participated in it, since it had been justified. The medieval public followed the same philosophy. They kept and welcomed prostitution into their communities.
Professor where I found one account : cla.umn.edu/rmk/
. . . .In medieval Europe, the Catholic Church not only condoned prostitution, but allowed it to be run out of the monasteries and convents. The phrase, “get thee to a nunnery” had nothing to do with a convent of “nuns” but rather the “nunnery” was a brothel. The exhortation was given to young men to keep them from trying to corrupt the virgin daughters of the townspeople.
In 1254, King Louis IX of France, decreed that all prostitutes be regarded as outlaws after it was discovered that a Parisian prostitute sat next to the queen of France in Church, and the queen, as was her custom, bestowed a kiss on her.When the identity of the woman reached the ears of the king, he decided that the only way to prevent future incidents was to outlaw prostitution throughout his kingdom. . . .
"Prostitution: An Illustrated Social History " Vern&Bonnie Bullough/ Crown Books 1978
History Channel website: In the Middle Ages the Christian church, which valued chastity, attempted to convert or rehabilitate individual prostitutes but refrained from campaigning against the institution itself. In so doing the church followed the teaching of St. Augustine, who held that the elimination of prostitution would breed even worse forms of immorality and perversion, because men would continue to seek sexual contact outside marriage. By the late Middle Ages, prostitution had reached a high point in Western history. Licensed brothels flourished throughout Europe, yielding enormous revenues to government officials and corrupt churchmen. . . .During the 16th century prostitution declined sharply in Europe, largely as the result of stern reprisals by Protestants and Roman Catholics. They condemned the immorality of brothels and their inmates, but they were also motivated by the perception of a connection between prostitution and an outbreak of syphilis, a previously unknown disease. Brothels in many cities were closed by the authorities. Under a typical ordinance, enacted in Paris in 1635, prostitutes were flogged, shaved bald, and exiled for life without formal trial.