In 1139, at the 2nd Lateran 10th Ecumenical Council, Pope Inocent II issued an anathema against "the deadly art, hated by
God, of crossbowmen..." This only applied to the use of crossbows against fellow
Christians. This anathema failed to stop the rise of crossbows, and it became a
favoured weapon of European mercenary companies.
Canon 29." We prohibit under anathema that murderous art of crossbowmen and archers,
which is hateful to God, to be employed against Christians and Catholics from now
on."
Other decrees:
Canon 14: "We entirely forbid, moreover, those abominable jousts and tournaments in
which knights come together by agreement and rashly engage in showing off their
physical prowess and daring, and which often result in human deaths and danger to
souls. If any of them dies on these occasions, although penance and viaticum are not
to be denied him when he requests them, he is to be deprived of a church burial."
Canon 18: " We completely detest and forbid, by the authority of God and the blessed
apostles Peter and Paul, that most dreadful, devastating and malicious crime of
incendiarism For this pernicious and inimical calamity surpasses all other kinds of
destruction. Nobody is unaware of the extent to which it is injurious to the people of
God and the damage it brings to souls and bodies. It is necessary, therefore, to
oppose it and to labour with all one's might, that so great a harm and danger be
eradicated and suppressed for the sake of the people. If anyone, then, after the
publication of this prohibition of ours, from some wicked design born of hate or
vengeance, starts a fire or causes it to be started, or knowingly provides counsel or
help to those starting one, let him be excommunicated. And when an arsonist dies,
he is to be deprived of a christian burial. Nor is he to be absolved unless, having first
made reparation for the loss according to his means, he swears that he will never
raise a fire again. Moreover, let him be given the penance of remaining a whole year
in Jerusalem or Spain in the service of God."
Canon 10: Excommunication of laymen who fail to Pay the tithes due the
bishops, or who do not surrender to the latter the churches of which they retain
possession, whether received from bishops, or obtained from princes or other
persons.
Seems to me the only practical one of these is the prohibition of arson
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"Quis custodiet ipsos custodes"