When Pope Benedict XVI proclaimed Saint Hildegard of Bingen a doctor of the Church in 2012, he praised the twelfth-century German mystic for the “significant influence” she exerted “both on the faithful and on important figures of her time.” Pointing to Hildegard’s writings on theology, liturgy, natural sciences, and music, the pope noted that today “her authority reaches far beyond the confines of a single epoch or society; despite the distance of time and culture, her thought has proven to be of lasting relevance.” The Holy Father went on to highlight that Hildegard’s work, “unmatched by any other female author of the Middle Ages,” “has great significance for today’s world and an extraordinary importance for women.”

In this essay, I argue that Hildegard’s thought is also relevant to just war thinking. While it would be a stretch to call her a political philosopher or even a just war thinker, Hildegard emphasizes the importance of the authority criterion in a way that is reminiscent of the writings of Saint Thomas Aquinas, who would systematize the classical just war about a century later. In particular, Hildegard, like Aquinas, builds on an account of virtue ethics. For Hildegard, internalizing the Christian virtues is a prerequisite of the good ruler. The virtues take on the function of a safeguard against misrule, which, of course, would also prevent the waging of unjust wars. I hold that Hildegard’s ideal of the virtuous ruler is remarkable in the sense that the medieval rediscovery of Aristotelian virtue ethics is commonly traced to Aquinas. Moreover, her conceptualization of right authority contrasts markedly with that of her contemporary Gratian, whose Decretum was the font of most medieval just war thinking. Gratian, in contrast to Hildegard’s linkage of virtue and political authority, held that the authority to wage war solely required the authority to issue a public decree.

Hildegard’s Letters: Corresponding with the Powerful of her Age

One of the most remarkable aspects of Hildegard’s work are the nearly four hundred letters of her correspondence with the powerful of the twelfth century, including popes, bishops, and highly influential Church figures such as Abbot Bernard of Clairvaux. Not only are her letters written in surprisingly blunt language, Hildegard also does not shy away from directly criticizing those senior dignitaries for what she sees as transgressions from the Christian faith.

For example, in a letter to Hillinus, the archbishop of Trier, Hildegard speaks of her age as a “squalid, womanish time.”[i] By that she means, following the medieval association of womanhood with weakness, that Church leaders had become forgetful about the very essence of the Christian faith. In particular, Hildegard objected to the Church leaders’ living off the fat of the land. That is why she, in her letters, time and again calls upon those in authority to return to ruling in accordance with the Christian virtues.

Importantly, while Hildegard speaks of a “womanish time,” the twelfth century was in no way one in which swords had been beaten into plowshares. In fact, it was the same century during which Bernard of Clairvaux made his influential call for holy war. Moreover, unlike today, many medieval bishops were prince-bishops, serving both as spiritual and political authority. James Turner Johnson, a leading scholar of the just war tradition, notes that the medieval understanding of political authority held that the sovereign was responsible for establishing the three ends of good politics, namely, order, justice, and peace.[ii] Following from these responsibilities, prince-bishops entertained armies and participated in wars. Thus, Hildegard’s urge for Church leaders to exhibit the Christian virtues goes beyond the spiritual realm and is relevant to worldly affairs, too.

Consider, for example, Hildegard’s letter to Bernard of St. Clement and Gregory of St. Angeli, two cardinal legates Pope Eugenius had sent to Germany to resolve a dispute with Emperor Frederick Barbarossa over the latter’s removal of bishops, including Bishop Heinrich of Mainz. Heinrich had been instrumental in obtaining papal sanction for Hildegard’s work at the Synod of Trier (1147–48), and Hildegard, albeit unsuccessfully, came to his defense. In the letter, Hildegard forcefully chastises those who in her eyes pursued Heinrich’s removal out of morally questionable motivations:

Now you, O emulators of the Most High, the Living Fountain cries out these things to you, because it is not fitting for you to have the eyes of the blind nor even a trace of the morals of vipers and the thievery of brigands, stripping bare the altar of God. Why, therefore, are you doing this? But because you are doing so, you are not able to loosen the Lord’s shoestring… Therefore, discipline yourselves.[iii]

Importantly, Hildegard does not just cry out against those who fail to follow Christ’s example, but also positively encourages bishops to rule virtuously. In her letter to Godfrey, bishop of Utrecht, she writes:

Now, O shepherd… seize justice in all your works, just as God foresaw all things before He made them, and rule your people in accordance with His will. Moreover, as Christ’s representative, give help to the people lest you be like a trumpet that only makes noise but does not work. Be a good aroma of virtue so that you may live forever… For when you understand that you occupy the bishop’s seat, praise God in all your ways and exalt Him in your good works, and cogitate on His precepts, repeating them tirelessly to the people… Make your God known by your honorable way of life, and magnify Him as the king in his judgments so that you may rule your people equitably and anoint them with mercy.[iv]

Admittedly, in her letters Hildegard does not explicitly link the ideal of the just ruler to the question of war and peace. However, she doubtlessly would have held that the virtues she highlights do apply to the complete set of a ruler’s responsibilities and, thus, would apply to just war thinking, too.


Hildegard’s place in history as the towering female scholar of the Middle Ages is secure. However, while she is commonly lauded as a polymath, her political thinking has not yet received much scholarly attention. I believe that her political theology is worthy of an in-depth investigation. While I do not want to go so far as to read a right of resistance against unjust rule into Hildegard’s thinking, her emphasis on the virtues, especially the cardinal virtue of justice, and charity, the highest of all virtues, is striking. For Hildegard, rulers who blatantly violate the virtuous example set by Christ lose their authority to rule. Following from that, an unvirtuous ruler would necessarily fail to be a right authority that can legitimately wage war. Given Gratian’s dominant but very different interpretation of right authority, Hildegard’s take can be seen as groundbreaking indeed.


Hildegard of Bingen. The Letters of Hildegard of Bingen. Volume I. Translated by Joseph L. Baird and Radd K. Ehrman. New York: Oxford University Press, 1994.

Johnson, James Turner. Sovereignty: Moral and Historical Perspectives. Washington, DC: Georgetown University Press, 2014.

[i] Hildegard of Bingen, “Hildegard to Hillinus, Archbishop of Trier,” in The Letters of Hildegard of Bingen. Volume I, trans. Joseph L. Baird and Radd K. Ehrman (New York: Oxford University Press, 1994), 88.

[ii] James Turner Johnson, Sovereignty: Moral and Historical Perspectives (Washington, DC: Georgetown University Press, 2014), 2.

[iii] Hildegard of Bingen, “Hildegard to Bernard and Gregory, Cardinals,” in The Letters of Hildegard of Bingen. Volume I, trans. Joseph L. Baird and Radd K. Ehrman (New York: Oxford University Press, 1994), 40.

[iv] Hildegard of Bingen, “Hildegard to Godfrey, Bishop of Utrecht,” in The Letters of Hildegard of Bingen. Volume I, trans. Joseph L. Baird and Radd K. Ehrman (New York: Oxford University Press, 1994), 116.