These sections are from The Tree of Battles of Honoré Bonet, translated by G.W. Coopland (Liverpool: Liverpool University Press, 1949).

Chapter V. WHETHER THE EMPEROR CAN DECLARE WAR AGAINST THE CHURCH
IN this part I ask whether the Emperor can make war against the Church, and, if he does so, whether his men and subjects, and the lords of his country, are obliged to help and obey in making such war on such command.

And as to this, I consider, in the first place, that his subjects should obey him, for the Emperor is the highest of princes, and the Scripture says that he who does not obey the prince must die. There is another reason : for the judgment and cognizance of making war belongs to the Emperor and to other princes, and why should their subjects be disobedient ? Another reason why they should obey is that, as the Pope should have obedience in spiritual matters, so the Emperor should have it in temporal things. But there is a still stronger reason, for, according to law, the subject must obey even a schismatic Emperor, and no clerk learned in law can deny this.

But I tell you that these arguments are very feeble, for the Emperor is procurator and defender of the Church, and it can hardly be sustained that he who is ordained to defend me should attack me. And, further, the Emperor is subject to the Pope, and the Pope is sovereign, and I do not see how the Emperor, being a subject, can have the power to judge in the cause of his superior. So the matter is clear enough. It is common knowledge that the Pope is sovereign of the Emperor, for he enquires if the election of the Emperor is valid, and if he is worthy to be Emperor, and also if his election has been properly carried out. And, what is more, if the Emperor does anything unseemly, the Pope takes away from him the imperial dignity ; wherefore it cannot be doubted that, if the Emperor orders such war, neither the princes nor the peoples of the Empire are required to obey him, or to make that war ; for according to the truth of the laws, subjects are not required to obey their sovereign when he commands anything against the will and command of God. But to persecute Holy Church is to offend the will and command of our Lord and the Commandment, for it is almost heresy. Therefore subjects are in no way required to obey in such conditions.

Now let us consider another matter.

Chapter VI. WHETHER THE POPE CAN DECLARE WAR AGAINST THE EMPEROR
NOW since we have seen above that the Emperor cannot ordain or declare war against the Church, we must consider whether the Pope can command war against the Emperor.

It would appear that he cannot, for the King's provost cannot do more than the King. It is clear that Jesus Christ our Lord never commanded war against His enemies, and thus, when He was taken by the Jews He commanded St. Peter expressly to put back his sword into his sheath, as the gospel bears witness. So how can the Pope, who is God's provost, do more than his lord? And a stronger reason-God said to His apostles : " Behold, the kings of this world are lords of their people and exercise seigiuory over them, but you shall not do thus," that is to say : " You shall not be lords, and the greatest among you shall be your servant." Whence it appears plain that our Lord God did not desire that they should have lordship ; and so, if the Pope has no lordship, how can he ordain and declare war against the Emperor ? Monseigneur St. Paul the Apostle also said that the members of the Church should not avenge themselves, but should conquer by patience ; and you know well that to make war does not accord with patience.

But though the reasons I have cited are in appearance good, yet I say to you in truth that, if the Pope found the Emperor to be schismatic or heretic or wishful to seize the possessions or territories or privileges of the Church, he could declare and ordain war against him, and all good Christians would be bound to aid the Pope, and also the subjects of the Emperor would be similarly bound. It happened thus in the time of the good Pope Alexander, the third of that name, whom the Emperor then reigning caused to flee into France. So the Pope ordered proceedings against the Emperor, and by sentence deprived him of the imperial dignity, and summoned to act against him the noble King of France, who did not refuse war against the Emperor and finally gained the upper hand. The first argument, to the effect that God commanded St. Peter to sheathe his sword, is of very little worth, for the truth is that our Lord Jesus Christ had commanded Himself to suffer death, and therefore did not wish to flee or escape it by the aid of man ; and also He did not say to St. Peter that he should relinquish his sword altogether, but that he should put it up into the sheath. Thus He wished to signify that Peter should keep his sword for the time to conic, for on that day He did not wish to be defended by it, but wished to endure suffering and death. And in the case of the other arguments I declare, in truth, that they are to be understood of the apostles and disciples of Jesus Christ, but by no means of the Holy Father to the effect that he should not have jurisdiction and power over all mortals.

Hence the true conclusion is that the Pope can order war against the Emperor in the case I have described above.