Five hundred years ago, Matthias Grünewald, Mr. Greenwood, painted an altarpiece for the Order of Saint Anthony in Isenheim. When I was young, I was entranced by it. I’ve never been to Isenheim, I couldn’t point to it on a map, I’ve only ever seen the image in books. I wanted to be an artist. I was an artist. The desire is the only qualification you need to be an artist, but I also wanted to be an art student, which is harder than being an artist because someone else has to make you an art student. So I used to draw at night. I’d drink bottles of beer and draw with soft pencils on soft paper. I’ve always been caught on the thorns of religious art.

At the time, I had no conscious, spiritual belief. Ours was an orthodoxly atheist household. I had just a vague fugitive and ethereal neediness. The art of faith is most obviously and heroically fraught with the central dichotomy and purpose of all art—that is, to render visible what can’t be seen, or perhaps to see more than is visible. At the most formal level, a painting of a landscape always represents something that no longer exists, in a place where it never existed. Religious art makes representation of an abstract. It is far more complex and metaphysically demanding than making an abstract representation of the physical, which passes the mental heavy lifting on to the viewer. The technical, emotional and intellectual conundrum of religious art is splendid, often in its failure, occasionally in its sublime transubstantiation of pigment, wood and cloth into the simulacrum of divinity. Grünewald’s Crucifixion is formally familiar. Christ on the cross faces us from the center of the picture; on either side are the ever-present Mary, his mother, fainting and supported by Saint John, and, kneeling at the foot of the cross, Mary Magdalene. On the other side is John the Baptist, looking oddly insouciant, the only participant who stares straight out at us. He is pointing at the dying Christ. His stance and the finger are oddly camp, as if he were saying, “Oh, get her!” but he also holds a book that tells us what he’s really saying: “Illum oportet crescere, me autem minui”: “He must become greater, but I must become less.” It is the self-deprecating reference to the Baptist’s relationship with Christ, even more so because he is already dead—he can’t be at the Crucifixion, because he is already headless. With him is a sheep who looks bored at constantly being roped in as a zoomorphic metaphor. But the main event of this picture is Christ. This is the most graphically horrifying murder. The sadistic awfulness of being nailed to a post. Most crucifixions are anodyne, tasteful, even elegant representations . . . polite enough to wear in gold on your cleavage or hang above a child’s bed. They are of the godly Christ, the one with the mission accomplished. He is sloughing the human to become the “great forgiver” . . . the true love. But you couldn’t live easily in a room with this, with Grünewald’s tortured body. This Christ is the man left behind with the agony. Too often crucifixions look like human washing hung out to dry into perfection. Chrysalises that you find on autumn twigs, a maggot that has become a butterfly. Christ, the awkward, soft halfling is become alabaster and choirs. It is the deific sacrifice, the sorry and the redemption, the gently reclining body swagged over Chippendale joinery that the church brands Ecce homo. But the Isenheim crucified Christ is Christ doubting, Christ forsaken, terrified, agonized. The man Christ dying by inches. His hands curled with the pain of the nails simultaneously implore the father he has never seen. It is the humanity of his death that is moving, more than the magician’s trick of empty sheets and moved rock. The Christ suffers the thorns of flagellation, splinters stick in his writhing body. He is covered in sores and open lesions. The monks of the Order of Saint Anthony specifically cared for peasants who had contracted Saint Anthony’s fire—an incurable condition that we now know as ergot poisoning. It comes from the mold on damp grain, which infects bread, and was endemic throughout the Middle Ages. Symptoms include running sores that led to gangrene, also hallucinations and horrors, skin crawling, shakes and itching. This Crucifixion is housed in a double-doored frame like a bank vault to hold the hideous truth of mortality. It was opened on the saint’s day; poor blighted patients would have seen Christ revealed with their symptoms. Not as a savior—there was no relief, no cure—but as a fellow sufferer.

I would return again and again to this image to be moved by its horror and its beauty, but mostly by its empathy. In the moment it was being painted, Michelangelo was finishing the Sistine Chapel ceiling. This is an artistic and moral age away from that bright power, the deific superhero god zapping life into Adam. This is still the dark and superstitious old time. A year after it was completed, Martin Luther nailed his theses to the door of the Wittenberg cathedral. This is a presentiment of a Protestant Christ, and the terrible irony is that as he is the bread that will feed humanity, the body reborn in sacrament wafers, so it was the bread that poisoned and tormented the poor believing peasants. The Bread of Heaven, the salt of the earth.

Retrospectively, I realized that the scabs of my own psoriasis mimicked the sores of Saint Anthony’s fire. The tingling of peripheral neuropathy, the hallucinations of the DTs, the skin crawling, were all small imitations of ergotism. What I was looking at in this Christ was the premonition of my own far more pathetic misery. So slowly I drew a portfolio of derivative and pretentious art, never really daring to go beyond the observed. I applied to art school in Falmouth. I didn’t want to go to Falmouth—who does?—and they in turn didn’t want me. But I did desperately want to go to Saint Martin’s in London. I’d never passed an exam and I’d left my odd vegetarian Quaker hippie school without sitting any A Levels. You needed at least two to go to art school. So in the summer holiday, I took A Level art as a private candidate. I also fell for my first real girlfriend. Rebecca. She was a New Yorker, the daughter of a family friend who was staying with us in London for six months. She was twenty-six, I was just eighteen. She was terrifying. Clever. Really, really clever and sternly pretty, with a brilliantly dry deadly humor. One night, stoically, firmly, with much hilarity, she took me to her bed, like someone teaching a simple child how to cross the road. Afterward, in the dark, her face lit by the rise and fall of a glowing shared No. 6, she asked if this was my first time. No, no. Not really. Well, technically, yes. She beamed and propped herself up on one elbow. “Good. Look, there’s going to be an awful lot of things you’re going to want to try. You’re a boy. And you’ve had way too long to think about all this. So relax. It’s okay. We will do everything—at least once. We’ve got all summer.” It is still the most generous and exciting thing anyone has ever said to me.

We all went to Skiathos. Rebecca, me, Mum, Dad and my little brother, Nick. When we finally got to the small house Dad had rented, it had just two rooms—one in the attic with three beds and one in the kitchen with two. It was clear to all of us that someone would be sharing with Nick. My mother took my father aside and had stern words and said to me, “You and Rebecca can have the kitchen.” It was a brilliant summer. I drank a lot of ouzo, we ate on cobbled streets, made friends. There was a dairy that served yogurt every evening. The first Greek yogurt I ever tasted, with bitter local honey. I stepped on a sea urchin. Someone told us how to get rid of the damnably painful spines that break under your skin and Rebecca hobbled me up to an olive grove, stepped out of her shorts and pissed on my foot. “I said we’d try everything.”

On the way to Skiathos, we stopped in Athens and went, of course, to the Acropolis and its museum. And something happened. I was walking through the great hot corridors of shattered antiquity with my father. The others were either behind or ahead of us and Dad was explaining, illuminating . . . this is what he liked doing most, talking in a museum. He was good at it, knowing just the right mix of academic and salacious. There is in all classical exhibits an overall, overwhelming sense of brokenness. Everything is a bit of something or is missing a bit. The recurring theme is not of creation but of destruction—you constantly try to repair the damage in your head, replace noses and arms, put back handles and spouts. We walked into a room and I burst into tears without warning. I was utterly overcome by sensation. There stood the blind Zeus—or perhaps he’s Poseidon—one of a handful of Greek bronzes and one of the most staggeringly transcendent artifacts that is left to us. Like the Grünewald Crucifixion, it is a god as a man. This is what the Renaissance was trying to rebirth, this huge heroic vision of us made eternal. He is naked with arms outstretched, one in front to aim and balance, one behind empty-handed, his thunderbolt or trident long gone. He has lost his glass eyes, he is blind. The cruciform arms also feel in the absence of light, reaching for the edge of something, both certain and tentative; he is powerful and vulnerable, so delicately balanced on the balls of his feet. There is a name for this sudden slap of art, this falling through the rabbit hole of civilization. It’s Stendhal syndrome: being overcome by beauty. They say that the guards in the Uffizi are trained to deal with collapsing Americans who have lived lives of blameless comfort in midwestern ugliness and can’t compute the full beam of a Bronzino. In my case, it has happened only a brief handful of times—two of them when I was with my father, which may be no accident. The first was when he took us to Venice. I must have been about fifteen. We got lost: everybody gets lost in Venice. There was something he wanted us to see at the end of a full day of seeing plenty. And the practiced authoritative chat had turned to irritation as we complained of the heat and sore legs and being gelato-less; but we walked and we walked and suddenly we were in a square, and there it was. And I caught a ragged breath and sobbed. Verrocchio’s Condottiere. Huge, totalitarian, aggressive, elegantly fascist. Not on anyone’s top ten of beautiful objects—but it pulses a superhuman imperious energy. There’s nothing vulnerable or lost about this man. But he is the patron of the old truth that it is better that people ask you why there is no statue to you than wonder why there is. Bartolomeo Colleoni the condottiero—literally a contractor. He was a mercenary who changed sides regularly, mostly between Venice and its rival, Milan, until the Venetians fixed him the way they fixed everything—with so much money he couldn’t say no.

When we got back home, my A Level result was on the mat. I’d passed. And there was an invitation from Saint Martin’s to come for an interview. Rebecca went back to New York and I to art school, where they said in an offhand way that I was welcome to join the foundation year but I really did need another exam. Would I take care of it? Yes, I said, I would. And no one ever asked for it again.