I will make it a point to check that book out of the library. It looks interesting. However, for a quick reference, here is what Wikipedia (not that I think that source should always be taken as gospel) has to say about the subject: (under the category of clerical celibacy)
Eleventh and Twelfth Centuries:
“The tenth century is claimed to be the high point of clerical marriage in the Latin communion (Catholic Church). Most rural priests were married and many urban clergy had wives and children....a large number of clergy, not only priests but bishops, openly took wives and begot children to whom they transmitted their benefices (Church property)...”
I know that that line has been repeated by many sources but I have never seen any documentation for the original source. Given the contrary evidence it is most likely pure invention.