UPDATE Citation/Quotation from Authoritative Source: "Here I wish to affirm once more that religion can never justify intolerance or war. We cannot kill in God's name!" (Benedict XVI, Verbum Domini, Post-Synodal Apostolic Exhortation, September 30, 2010, Part 3)
Compare to the Holy Land Decrees of the Fourth Council of the Lateran (source for translation):
Desiring with an ardent desire to liberate the Holy Land from the hands of the ungodly, we decree with the advice of prudent men who are fully familiar with the circumstances of the times, and with the approval of the council, that all who have taken the cross and have decided to cross the sea, hold themselves so prepared that they may, on June 1 of the year after next (1217), come together in the Kingdom of Sicily, some at Brundusium and others at Messana, where, God willing, we (the Pope) will be present personally to order and to bestow on the Christian army the divine and Apostolic blessing. Those who decide to make the journey by land, should strive to hold themselves prepared for the same time; for their aid and guidance we shall in the meantime appoint a competent legate a latere. Priests and other clerics who are with the Christian army, subjects as well as prelates, must be diligent in prayer and exhortation, teaching them (the crusaders) by word and example that they have always before their eyes the fear and love of God, lest they say or do something that might offend the majesty of the eternal King. And should any have fallen into sin, let them quickly rise again through true repentance, practicing humility both interiorly and exteriorly, observing moderation in food as well as in clothing, avoiding dissensions and emulations, and divesting themselves of all malice and ill will, that being thus fortified with spiritual and material arms, they may fight with greater success against the enemies of the faith, not indeed relying on their own strength but putting their trust in the power of God. To the clerics we grant for a period of three years as complete an enjoyment of their benefices as if they actually resided in them, and they may, if necessary, even give them as pledges during this time. Therefore, that this undertaking may not be impeded or retarded, we strictly command all prelates that each one in his own territory induce those who have laid aside the crusader's cross to resume it, and carefully to admonish them and others who have taken the cross, as well as those who happen to be engaged for this purpose, to renew their vows to God, and if necessary to compel them by excommunication and interdict to abandon all delay.Yes, yes - I know the usual retort: Benedict XVI was not speaking infallibly in the instance above.
Moreover, that nothing connected with the affairs of our Lord Jesus Christ be omitted, we wish and command that patriarchs, archbishops, bishops, abbots, and others who have the care of souls, diligently explain the meaning of the crusade to those committed to them, adjuring-through the Father, Son, and Holy Ghost, one, only true, and eternal God-kings, dukes, princes, marquises, counts, barons, and other prominent men, as well as cities, villages, and towns, that those who cannot go personally to the Holy Land, will furnish a suitable number of soldiers and, for a period of three years, in proportion to their resources, will bear the necessary expenses connected therewith for the remission of their sins, as we have made known in the general letters already sent over the world and as will be,exprcssed in greater detail below. In this remission we wish not only those to participate who for this purpose furnish their own ships, but those also who undertake to build ships. To those declining to render aid, if perchance any should be found to be so ungrateful to God, the Apostolic See firmly protests that on the last day they will be held to render an account to us in the presence of a terrible judge. Let them first consider with what security they can appear in the presence of the only begotten Son of God, Jesus Christ, into whose hands the Father has given all things, if in this matter they refuse to serve Him who was crucified for sinners, by whose favor they live, by whose benefits they are sustained, and by whose blood they were redeemed.
But, lest we should seem to place grave and unbearable burdens on the shoulders of the people, we ourselves (the Pope) donate to the cause what we have been able to save by strict economy, 30,000 pounds, besides a ship to convey the crusaders from Rome and vicinity and 3,000 marks silver, the remnant of alms received from the faithful. The remainder we have given to Albert patriarch of Jerusalem, and to the masters of the Temple and Hospital for the necessities of the Holy Land. With the approval of the council we further decree that absolutely all clerics, subjects as well as superiors, shall, in aid of the Holy Land and for a period of three years, pay into the hands of those appointed by the Apostolic See for this purpose, one twentieth part of ecclesiastical revenues; some religious orders only being excepted and those (clerics) also who take or already have taken the crusader's cross and are about to set out personally. We and our brethren, the cardinals of the Holy Roman Church, will pay one-tenth of our revenues. All are bound to the faithful observance of this under penalty of excommunication, so that those who deliberately commit fraud in this matter will incur that penalty.
Since by the just judgment of the heavenly King it is only right that those who are associated with a good cause should enjoy a special privilege, we exempt the crusaders from collections, taxes, and other assessments. Their persons and possessions, after they have taken the cross, we take under the protection of Blessed Peter and our own, decreeing that they stand under the protection o f the archbishops, bishops, and all the prelates of the Church. Besides, special protectors will be appointed, and, till their return or till their death shall have been certified, they shall remain unmolested, and if anyone shall presume the contrary, let him be restrained by ecclesiastical censure.
In the case of crusaders who are bound under oath to pay interest, we command that their creditors be compelled to cancel the oath given and to cease exacting interest. Should any creditor force the payment of interest, we command that he be similarly forced to make restitution. We command also that Jews be compelled by the secular power to cancel interest, and, till they have done so, intercourse with them must be absolutely denied them by all Christians under penalty of excommunication. For those who cannot be their departure pay their debts to the Jews, the secular princes shall provide such a delay that from the time of their departure till their return or till their death is known, they shall not be embarrassed with the inconvenience of paying interest. If a Jew has received security (for example, a piece of ground) for such a debt, he must, after deducting his own expenses, pay to the owner the income from such security. Prelates who manifest negligence in obtaining justice for the crusaders and their servants, shall be subject to severe penalty.
Since the corsairs and pirates too vehemently impede assistance to the Holy Land by capturing and robbing those who go there and those returning, we excommunicate them and their principal abetters and protectors, forbidding under threat of anathema that anyone knowingly hold intercourse with them in any contract of buying and selling, and enjoin upon the rulers of cities and their localities that they check and turn them away from this iniquity. And since an unwillingness to disturb the perverse is nothing else than to favor them, and is also an indication of secret association with them on the part of those who do not resist manifest crime, we wish and command that severe ecclesiastical punishment be imposed by the prelates on their persons and lands. We excommunicate and anathematize, moreover, those false and ungodly Christians who furnish the enemies of Christ and the Christian people with arms, iron, and wood for the construction of ships; those also who sell them ships and who in the ships of the Saracens hold the post of pilot, or in any other way give them aid or advice to the detriment of the Holy Land; and we decree that their possessions be confiscated and they themselves become the slaves of their captors. We command that this sentence be publicly announced in all maritime cities on all Sundays and festival days, and that to such people the church be not opened till they return all that they have obtained in so reprehensible a traffic and give the same amount of their own -in aid of the Holy Land. In case they are not able to pay, then let them be punished in other ways, that by their chastisement others may be deterred from undertaking similar pursuits.
Furthermore, under penalty of anathema, we forbid all Christians for a period of four years to send their ships to Oriental countries, inhabited by the Saracens, in order that a greater number of ships may be available to those who wish to go to the aid of the Holy Land, and that to the Saracens may be denied the benefits that they usually reap from such commercial intercourse.
Though tournaments have been, under certain penalties, generally forbidden by different councils, since however at this time they are a serious obstacle to the success of the crusade, we strictly prohibit them under penalty of excommunication for a period of three years.
But, since for the success of this undertaking it is above all else necessary that princes and Christian people maintain peace among themselves, we decree with the advice of the holy council that for four years peace be observed in the whole Christian world, so that through the prelates discordant elements may be brought together in the fulness of peace, or at least to the strict observance of the truce. Those who refuse to acquiesce in this, are to be compelled by excommunication and interdict, unless the malice that inspired their wrongdoings was such that they ought not to enjoy such peace. But, if by chance they despise ecclesiastical censure, they have every reason to fear lest by the authority of the Church the secular power will be invoked against them as disturbers of the affairs of the One crucified.
We, therefore, by the mercy of the omnipotent God, trusting in the authority of the Blessed Apostles Peter and Paul, in virtue of that power of binding and loosing which God has conferred on us, though unworthy, grant to all who aid in this work personally and at their own expense, a full remission of their sins which they, have sincerely repented and orally confessed, and promise them when the just shall receive their reward an increase of eternal happiness. To those who do not personally go to the Holy Land, but at their own expense send there as many suitable men as their means will permit, and to those also who go personally but at the expense of others, we grant a full remission of their sins. Participants of this remission are, moreover, all who in proportion to their means contribute to the aid of the Holy Land, or in regard to what has been said give opportune advice and assistance. Finally, to all who in a spirit of piety aid in bringing to a successful issue this holy under. taking, this holy and general council imparts the benefits of its prayers and blessings that they may advance worthily to salvation. Amen.
But isn't there a more obvious issue? Benedict XVI's beliefs on this subject are clearly in disagreement with those of medieval Rome.