65. In his Comment. on the words "from strangled animals and blood" (Acts 15), Calmet states that some Latin churches distinguished between clean and unclean foods and abstained from blood and strangled meat as late as the tenth and eleventh century. He does not at this point offer any proof for his statement but its truth is quite evident to anyone who has the slightest acquaintance with Christian writing. For Canisius published an old Roman penitential from the end of the eighth or the start of the ninth century; under the heading "On strangled meat," it prescribes a penance for eating the meat of a strangled animal, and under the heading "On mangled flesh," it prescribes penances and fasts for eating fish which died in the pool or for drinking water from a well in which a mouse or a hen died before thoroughly cleansing the well.

Humbertus, Cardinal of Silva Candida, as Legate of Pope St. Leo IX at Constantinople, argued violently with the Greeks, but he openly admitted during the disputations that on this subject Latins and Greeks did not disagree since this practice was still observed in some Latin and Greek churches. "Maintaining the ancient custom or tradition of our fathers, we too hold these things in abomination; apart from the great danger to life, a heavy penance is imposed on those among us who eat blood or corpses or polluted waters or animals which died by accident." And elsewhere he says, "So even though the Lord and the Apostles give us permission to eat everything which does not harm our own health nor that of our brother, the custom of some areas and the precepts of our fathers make us abstain from some foods. We do this not because they are bad or unclean, but either because at times they are not expedient, or they revolt us now that longlasting habit has become nature for us."