Soldiers in Sudan's army celebrate after entering Wad Madani, Sudan, Jan. 12. (OSV News/Reuters/El Tayeb Siddig)
As civilian deaths from warfare climb around the world, a solution to this inhumanity may be found in two official Catholic movements originating nearly 1,000 years ago.
The Peace of God and the Truce of God emerged from the trauma of the 10th century. Conflicts with the Holy Roman Empire, the Byzantine Empire, between Christians and Muslims in Spain, and a surge in raids by Vikings across Europe devastated civilian populations.
These two medieval movements — which established the rules of war in an era of swords and crossbows — have never been more relevant than they are today.
Civilian deaths worldwide surged in 2024 by 40%, the third consecutive year of increasing noncombatant fatalities in armed conflicts, according to data released by the U.N. Human Rights Office in June. In Ukraine, Sudan, Myanmar, Gaza and elsewhere, the targeting of civilians — as well as hospitals, schools, churches, apartments and other civilian buildings and infrastructure — is on the rise.
A fire-fighting helicopter collects water to control a fire after Russian missile and drone strikes in Kyiv, Aug. 28. (OSV News/Reuters)
In Ukraine, the number of civilians killed and injured by Russian troops, missiles and drones reached a three-year monthly high in July. Only during the first three months after Russia's February 2022 invasion were there more Ukrainian civilian casualties. More than 15,400 Ukrainian civilians have been killed since the beginning of the war, according to the U.N. Although estimates vary, civilians wounded or killed by Ukrainian forces in Russia or in Russian-occupied areas of Ukraine are, by far, fewer.
In Sudan, the brutal civil war between Sudan Armed Forces (SAF) and the paramilitary Rapid Support Forces (RSF) has killed or wounded over 17,000 civilians since April 2023. In Myanmar, the civilian death toll has been high ever since the military coup in February 2021.
In Gaza, more than 67,000 Palestinians have reportedly been killed by Israeli Defence Forces in the wake of the Oct. 7, 2023, terrorist attack in Israel, when Hamas and other militant groups murdered approximately 800 Israeli civilians and foreign nationals. In May a classified Israeli military intelligence database indicated that 5 out of 6 Palestinian deaths have been civilians.
A core criterion of just war theory is noncombatant immunity, and armed forces are expected to distinguish between combatants and noncombatants, as well as to try to avoid or minimize civilian casualties. Militaries are prohibited from intentionally targeting noncombatants, although their foreseeable deaths and injuries may be permitted as "collateral damage" as long as these are not intended and not disproportionate. In other words, militaries have a duty of "due care" to avoid harming noncombatants and of "constant care" to minimize harm to them, even if doing so means taking risks on the part of combatants.
This moral duty to respect noncombatants, rooted in just war theory, was enshrined in international law, including the Hague and Geneva conventions. However, I worry that while all of that was one step forward, we are now witnessing two steps being taken backward — as evident when the U.S. secretary of "war" Pete Hegseth told the generals and admirals gathered at Quantico, "We don't fight with stupid rules of engagement" but rather with "maximum lethality."
If governments, including our own, and non-state actors are now going to flagrantly disregard and violate these principles, then perhaps it is time for the church to retrieve the Peace of God and the Truce of God.
A poster with a picture of Oded Lifshitz, 84, who was kidnapped during the deadly Oct. 7, 2023, attack by Hamas, is placed on a chair on the day of a commemorative memorial in Kibbutz Nir Oz, southern Israel, Oct. 6, 2025. Lifshitz was later killed in captivity. (OSV News/Reuters/Amir Cohen)
In his classic book, The Just War in the Middle Ages, historian Frederick H. Russell observes that following "the chaos of the tenth century" church synods and councils promulgated the Peace of God and the Truce of God. The former declared certain persons to be immune from violent attack, and the latter limited the use of armed force to certain time periods.
The Peace of God stipulated that the following people should not be attacked: monks, clerics, nuns, women, merchants, shepherds, pilgrims, peasants and visitors to councils. Even sheep and olive trees were not to be targeted. The Council of Narbonne in 1054 decreed that churches and their surrounding grounds, as well as cemeteries and cloisters, were to be exempt from violence. Hospitals, too, would be included in the Peace of God.
The Truce of God excepted Sundays, Fridays, holy days, feast days and whole church seasons (such as Advent and Lent) from warfare. The Proclamation of the Truce at Besancon and Vienne (ca. 1041 CE) stated: "We command all to keep the truce from sunset on Wednesday to sunrise on Monday, and from Christmas to the octave of Epiphany, and from Septuagesima Sunday to the octave of Easter." Warfare during these times was unacceptable.
"For a just war to remain a just war," Russell writes, "it had to be conducted properly, which meant that it could only be waged on other soldiers."
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Rather than no longer teaching or using just war theory, as some have urged, I propose reclaiming and recommitting ourselves to its principles. Catholics belong to an international community and institution, and our retrieval of the Peace of God and the Truce of God will raise attention to, and accountability for, indiscriminate and disproportionate civilian casualties — and perhaps lead to the avoidance and minimalization of further noncombatant injuries and deaths.
Indeed, in Ireland such a retrieval has already been proposed. Inspired by the "law of the innocents" (lex innocentium) from Adomnán (624-704 CE), abbot of Iona, and accepted by the Synod of Birr in 697 CE, there is a call, launched in Birr a year ago, for a new Lex Innocentium for the 21st century. In addition to people and places, this new version of the Peace of God ecologically extends protection to the planet. It also expands the Truce of God to encompass any time and every day.
One need not be a pacifist to be committed to reversing the current spike in civilian casualties. Catholics who, like myself, continue to think that limited armed force may sometimes be necessary to defend the innocent should also support this effort.
After all, as noted by Russell and Fahey, it is precisely such a moral perspective that gave rise to the protection of the innocent as stipulated by Peace of God and the Truce of God.
