I credit the singer-songwriter Donovan with introducing me to Saint Francis of Assisi. I credit also Franco Zeffirelli, director of the Donovan-scored Brother Sun Sister Moon (1972), and Paolo Belardo, my tenth-grade Italian teacher, who suspended all learning for a week to screen the film. But my low-heat fervor for the saint developed mainly as a result of my response to Donovan’s soundtrack, a gentle, hippie sing-along that became the most durable joke of my sophomore year. In lyrics like “Fish are in love with the water / Birds are in love with the air,” my friends and I had encountered a record amount of sappy earnestness, to which the only appropriate teenage response was ridicule. To make each other laugh, we would assume dreamy looks, loll our heads to one side, and warble about birds, butterflies, and flowers, about personified celestial bodies, while swaying our arms and hips. Were we popular? Not always.

But in my barely hidden self, I actually had no problem loving flowers, and the basic facts of Saint Francis’s life held immense appeal. A good-looking party boy, a prince of the popolo, renounces his possessions and societal privilege; embraces nature, poverty, and charity; walks the Umbrian countryside barefoot; clothes himself in a coarse habit bound by a cord; builds quaint churches; preaches penance; does mercy unto lepers—and amazes everyone. What more could a teenager ask than to stun the world with his previously hidden quality of being?

I was at an age—beginning to understand that I would be responsible for the life I live, not yet knowing all that would be impossible or ridiculous to attempt—when I believed I might somehow shape my life by the same principles. I would cast off the looming demands of adulthood, striving toward a perfect existence, one that didn’t traffic in arbitrary systems of civilization, one that connected directly to the great benevolent truth of creation. A remote and fairly self-important possibility, sure. But Francesco di Bernardone himself didn’t convert to his simple life until he was twenty-five years old, meaning that I had another ten years of saint-sanctioned debauchery before I had to submit to any kind of holy vision.

Even as I moved further from any notion of saintliness, I continued to feel a secret affinity with the Poor Man of Assisi. However silly the origins of the interest, I was still intrigued to pick up André Vauchez’s Francis of Assisi: The Life and Afterlife of a Medieval Saint, translated from the French by Michael F. Cusato, O.F.M. The book seeks to place St. Francis in his historical context, to describe his actions and qualities as a living person, and to consider centuries’ worth of interpretive portraits, peeling away layers of legend and interest to weigh the remaining biographical value. The occasion for this renewed portrait is the “harvest” of the last forty years of scholarship. The result is an indispensable document attesting to what can be known of the Poor Man of Assisi, as well as a stirring exemplum of written history.

The approach appealed to me: while I grew up Catholic and, in a haunted way, still am, I don’t have the conviction to claim value in the supernatural aspects of Francis’s hagiographical existence. I hoped somehow to justify my longstanding affinity on factual, rather than spiritual, grounds. In this regard, Vauchez, an expert of medieval Christianity, does not skimp. He overwhelms. He treats the incredible episodes of the Poor Man of Assisi’s life with sensitivity—the receiving of the stigmata being the most crucial—and recognizes their importance in shaping the figure of Saint Francis. He quotes from Charles Perrot, who wrote in his 2000 biography of Jesus: “Today the historian is not so much the one who declares a historical truth with fresh new facts, but one who slowly learns what one cannot say about the object of one’s desire.” Vauchez doesn’t say a lot. He abstains from conjuring the mythical figure of Saint Francis, the one that has navigated the globe and achieved the status of supersaint. Instead he frames his subject with what the facts, or probable facts, allow. Vauchez’s biography sheds a number of his legendary characteristics—he didn’t have a particular fondness for animals, for one; he just loved creation, of which they happened to be a part (subtle difference, but still.)

Born either in 1181 or 1182, Francis grew into a jubilant and confident young man. In 1202, while imprisoned in Perugia after the battle at San Giovanni Bridge, he boasted to his cellmates: “Know that one day I will be venerated throughout the whole world!” (I have said equally absurd things to women and friends in my life, but Francis turned out to be right.) His conversion came not at once but after a process of several years; time enough to allow for a true redirection of a human heart. His following grew out of a charisma animated by “fundamental certitudes” and serendipitous political circumstances. His vow of poverty allowed him to become, as Vauchez writes, “an artisan of concord between human beings.” Possessing no goods, abhorring money, and seeking peace for its own sake, he was an ideal broker in conflicts large and small. He believed in the purity of his inspiration and demanded that its resulting rule be followed without interpretation.

To make his message plain, Francis sought to eliminate the distance between his words and his actions, proposing himself as a model to his order, applying “a hierarchy of example through his own personal witness.” Most famously, in the summer of 1219, the Poor Man of Assisi arrived in Damietta, a crucial port on the Nile Delta, held by the sultan al-Malik al-Kamil. Troops of the Fifth Crusade had been besieging the city for almost a year to no decisive result. After an offensive by the Crusaders ended in bloody defeat, a truce was called. Francis made his move, leaving the Christian camp, approaching enemy lines, calling out the sultan’s name. The sultan granted him an audience and the Poor Man of Assisi remained in the enemy camp for several days. Contemporary sources attest to the historicity of the event. But even they must speculate as to what occurred between the sultan and the monk. Did Francis denounce Islam? Did he try to convert the sultan? Was his holiness tested? Was he tortured? What’s certain is that he wasn’t killed—an astounding feat considering the martial context. One clue to his survival can be found in the Franciscan rule of 1221:

The brothers who go thus [among the Muslims] can envisage their spiritual role … by not making accusations or disputes, but being subject to every human creature for the sake of God and simply confessing they are Christians.

Unlike Mother Church, who viewed Islam as its greatest enemy, Brother Francis approached the other faith in the love of God. But the prescription of respect proved too innovative for the Church and disappeared only two years later in the rule of 1223.

Even prior to his death in 1226, as the Friars Minor, as they were now known, transitioned from a tolerated brotherhood into a recognized order, the Poor Man of Assisi’s message had become subject to the interpretation of the order’s administrative authorities. While certain aspects of his rule progressed without his direct supervision, he remained until the end of his life their spiritual leader. In April or May of 1225, Francis, suffering from an ocular infection, after having received some who-can-believe-this-didn’t-work medical treatment—namely, the cauterizing of his temples with a branding iron—convalesced in a cell at San Damiano, home of Saint Clare. In agony, chastised by the overabundant mice, the Poor Man of Assisi felt somewhat forgotten by his Lord, and despaired. Until, that is, he received from God “the surety of his salvation.” The next morning, at what must be considered the heights of mortal joy, he composed the Canticle of Brother Sun. In this work, Francis praises the glory of creation and finds God not separate and above this world but in the objects and creatures of its making. Curiously, Christ is not named in the Canticle. Instead, at the end of his holy and ascetic life, having just been assured of eternity in heaven, Francis honors the physical world.

Vauchez tracks the evolution of the saint’s figure from the time of the canonization through the Reformation, the saint’s rediscovery by the Romantics in the nineteenth century, and his appropriation by groups of every stripe in the present day (though nowhere does he mention Brother Sun Sister Moon). Roberto Rossellini’s Flowers of Saint Francis does rate a mention, and perhaps it’s understandable that Rossellini, a clear-eyed realist, should meet with an historian’s approval. His portrait conveys the humility and the evangelical enthusiasm of the earliest years of Francis’s brotherhood, whereas that offered by Zeffirelli rings about historically accurate as Judas Iscariot’s personal style in Jesus Christ Superstar. And yet I forgive myself for loving Brother Sun Sister Moon.

This past summer, I visited Assisi for an afternoon. I wish I had stayed longer. My wife and I, along with another couple, were on our way from Siena to Perugia, where we would be staying the night. And there was a slight passport issue—mine was missing—so our capacity for appreciation was somewhat compromised. We hiked up to La Rocca, the medieval fortress capping the hill town. We looked northeast to the evergreen flank of Monte Subasio, pocked with unseen hermitages. To the south, the Umbrian countryside unfurled like plush sod. And perched on the western edge of the city was the Basilica di San Francesco, built in the years immediately after Francis’s death. Later, inside the Basilica, after cramping our necks to view Giotto’s frescoes, we descended into the crypt. The tomb of Saint Francis consists of two pieces of roughly hewn, unadorned, gray rock. Visitors walked quietly down the aisle, past rows of pews, and many knelt by the tomb to pray. I was excited, awed even, to be near a physical remnant of an individual who had existed only in my imagination and at great removes of time and place. I quieted. And then I left. On our way to the exit, we passed through the gift shop. I bought a silver chain with a pendant of Saint Francis in profile. Brother Sun Sister Moon held pride of place in the DVD section. Outside, in the lower piazza, a young monk threw a Frisbee.

Michael Signorelli is an editor at HarperCollins Publishers. His writing has appeared in Cousin Corinne’s Reminder, Howler, McSweeney’s Internet Tendency, and elsewhere.