hi all,
I ran across this forum while doing an internet search, which has so far been fruitless. I am a retired type, who has taught history off and on during a checkered career.
At the dog park this morning, we were discussing unusual weapons for possible murders. this is purely a literary issue, since one of the regulars writes murder mysteries, which are pretty decent reads. [Carol Newsome, check her out on
Amazon].
I mentioned that the Church in the Middle Ages tried to impose rules on warfare, such as banning the use of the crossbow on Christians. I easily found a reference to the Second Lateran Council of 1139, which may have stated such a rule.
I also mentioned something I had heard in grad school some 40 years ago. my main field was modern Europe, but I did take a couple of medieval history seminars. I have a vague recollection of the prof mentioning that a medieval Pope, irate at the participation of priests, bishops, etc inlocal wars, had issued an edict forbidding the clergy from drawing the sword in battle. This, he claimed, led to an inventive bishop coming up with the flail.
my internet searches have not turned up anything to back this up.
Would anyone have light to shed on this question?

http://manuscriptminiatures.com/4844/7678/
[ Linked Image ]

It depends on the region and time period. Sometimes clergy were forbidden to fight at all. Sometimes they were rewarded for fighting. Sometimes they could fight if they had a just cause. Sometimes they could fight if it wasn't against Christians. The main work that discusses clerics and whether they can fight is Thomas Aquinas' Summa Theologiae. In this work he draws upon many prominent thinkers including Aristotle, Dionysius, Rabbi Moses, Augustine, and Peter Lombard. Aquinas introduces the concept of "non-combatants" and said that a member of the clergy had permission to be on the battlefield, but they could not actively fight. Thomas wrote that war is forbidden to a cleric because war is secular in nature and it was beneath the clergyman to engage in such "earthly" practices. He further states that they should not, "slay or shed blood" because they would become tainted and no longer capable of performing their primary duty as a member of the Church, i.e. "ministry of the altar." Here is an interesting passage about a mace-wielding cleric at the Battle of Bouvines in 1214. William of Breton describes the actions of Philippe de Dreux, Bishop of Beauvais:

"Indeed, the Bishop of Beauvais… became unhappy, and since by chance he happened to have a mace in his hand, hiding his identity of bishop, he hits the Englishman on the top of the head, shatters his helmet, and throws him to the ground forcing him to leave on it the imprint of his whole body. And, since the author of such a noble deed could not remain unnoticed, and since a bishop should not be known to have carried arms, he tries to hide as much as possible and gives orders to John… to put the warrior in chains and to receive the prize for the deed. Then the bishop, throwing down several more men with his mace, again renounces his titles of honor and his victories in favor of other knights so as not to be accused of having done work unlawful for a priest, as a priest is never allowed to be present at such encounters since he must not desecrate either his hands or his eyes with blood. It is not forbidden, however, to defend oneself and one’s people provided that this defense does not exceed legitimate limits.

But there are plenty of counter examples of bishops and priests fighting and shedding blood. At the Battle of Otterburn in 1388, Froissart mentions William of North Berwick, a Scottish deacon who distinguishes himself with a battleaxe. This man was not chastised for his actions – rather, he was promoted for his valour to the position of Archdeacon of Aberdeen later in the same year. When Pope Julius II commissioned Michelangelo to sculpt a bronze statue of himself and was asked if he would like to be depicted with a book in his hand, the Pope allegedly replied, "Why a book? Show me with a sword." There were five hundred priests wielding spears at the Battle of Durham Field (1346) and they were led by their axe-wielding Bishop. This is from the Lay of Durham Field

Five hundred priests said mass that day
In Durham in the field,
And afterwards, as I hard say,
They bare both spear and shield. [XLIV]

The Bishop orders himselfe to fight,
With his battell-axe in his hand;
He said, ‘This day now I will fight
As long as I can stand!’ [XLV]

I have a long list of other examples.

i don't think the idea of clergy being on the battlefield as out of the ordinary in 9th-10th century. a bishop had the task of protecting church lands - in much the same way a knight was protecting a lords lands. in the Song of Roland the Bishop is depicted as a close second in prowess in battle to Roland himself. although this is a writing from that time period it is still loosely based on facts.

there are a lot of readings that most priest came from noble families to begin with - noble families with military backgrounds, it seems only natural that clergy men would attempt to find an outlet for their warring nature. and I'm pointing more toward the 9-10th century, post Norman conquest era (Brittan and Sicily)

in my first crusade research - you constantly read about the bishop Adhemar of Le Puy, the 'secular' leader of the crusade. although there is no written evidence that he was a combatant in battle - chances are he would have looked like another knight on the field. Anna Comnena gives very detailed descriptions of the princes of the Crusade but i do not believe one is given on Adhemar.

An amateur overview of this issue, not very detailed or academically rigorous but fairly readable:

http://l-clausewitz.livejournal.com/394539.html

Bishop Odo wielding a Mace
[ Linked Image ]

I've heard that priests wielding blunt instruments like the mace or flail was a Victorian invention. The use of a mace or club was due to it being a symbol of authority, and not due to any prohibition on shedding blood (as anyone who has seen a blunt force trauma will attest to)

The whole manuscript's available online. If you want a clearer picture of the entire page, go here:
http://www.e-codices.unifr.ch/en/vad/0302/II_35v/x-large