What was the black-winged god of love? The insights that masterwork uncovers about the rogue genius

A youthful boy screams as his skull is forcefully gripped, a massive digit pressing into his face as his father's powerful palm grasps him by the throat. That scene from Abraham's Sacrifice visits the Florentine museum, creating distress through the artist's chilling portrayal of the tormented youth from the biblical account. The painting seems as if the patriarch, commanded by the Divine to kill his offspring, could snap his neck with a solitary turn. Yet the father's preferred method involves the silvery steel blade he holds in his remaining hand, prepared to cut Isaac's throat. One certain element stands out – whoever modeled as the sacrifice for this astonishing work demonstrated remarkable acting skill. Within exists not just fear, shock and pleading in his darkened gaze but also deep sorrow that a guardian could abandon him so completely.

He took a well-known scriptural story and made it so vibrant and raw that its terrors seemed to happen directly in view of the viewer

Viewing before the painting, viewers identify this as a actual face, an accurate record of a young subject, because the identical boy – identifiable by his tousled locks and nearly dark eyes – features in several other works by Caravaggio. In each instance, that richly expressive visage commands the composition. In Youth With a Ram, he peers mischievously from the shadows while holding a ram. In Amor Vincit Omnia, he grins with a toughness acquired on Rome's alleys, his dark plumed appendages demonic, a naked adolescent running chaos in a well-to-do dwelling.

Victorious Cupid, currently displayed at a London gallery, represents one of the most embarrassing artworks ever created. Viewers feel totally unsettled gazing at it. Cupid, whose arrows fill people with often painful desire, is shown as a extremely tangible, brightly illuminated unclothed form, straddling overturned objects that include stringed devices, a musical score, metal armor and an builder's T-square. This heap of items echoes, intentionally, the geometric and architectural gear scattered across the ground in the German master's print Melencolia I – except in this case, the gloomy disorder is caused by this smirking deity and the turmoil he can release.

"Love looks not with the vision, but with the mind, / And thus is winged Love depicted blind," penned the Bard, just prior to this work was created around the early 1600s. But the painter's Cupid is not unseeing. He stares straight at you. That face – sardonic and rosy-faced, looking with brazen assurance as he struts naked – is the same one that shrieks in terror in The Sacrifice of Isaac.

As Michelangelo Merisi da Caravaggio created his multiple portrayals of the same distinctive-appearing youth in the Eternal City at the start of the seventeenth century, he was the most acclaimed religious artist in a city enflamed by religious revival. The Sacrifice of Isaac reveals why he was sought to adorn churches: he could adopt a scriptural story that had been depicted many occasions previously and make it so new, so raw and visceral that the terror seemed to be occurring directly before the spectator.

However there was another aspect to Caravaggio, evident as quickly as he came in the capital in the winter that concluded the sixteenth century, as a painter in his early twenties with no mentor or supporter in the city, only skill and audacity. The majority of the paintings with which he captured the sacred metropolis's eye were everything but holy. That may be the very first resides in London's art museum. A young man parts his crimson lips in a scream of pain: while reaching out his dirty fingers for a fruit, he has rather been attacked. Boy Bitten By a Lizard is sensuality amid poverty: observers can see Caravaggio's dismal chamber reflected in the murky waters of the transparent vase.

The boy wears a rose-colored flower in his hair – a emblem of the sex trade in Renaissance painting. Venetian artists such as Tiziano and Palma Vecchio portrayed prostitutes holding flowers and, in a painting destroyed in the second world war but known through images, Caravaggio represented a famous female courtesan, clutching a bouquet to her bosom. The meaning of all these botanical signifiers is obvious: intimacy for sale.

How are we to make of the artist's sensual portrayals of boys – and of one adolescent in specific? It is a inquiry that has divided his interpreters since he achieved widespread recognition in the twentieth century. The complex historical truth is that the painter was neither the queer icon that, for instance, Derek Jarman presented on film in his 1986 film about the artist, nor so completely devout that, as certain art historians improbably claim, his Boy With a Basket of Fruit is in fact a likeness of Christ.

His initial paintings do offer explicit erotic suggestions, or even propositions. It's as if the painter, then a penniless young creator, aligned with the city's sex workers, selling himself to survive. In the Uffizi, with this idea in mind, viewers might look to an additional early work, the sixteenth-century masterpiece the god of wine, in which the deity of wine stares coolly at the spectator as he starts to undo the dark sash of his robe.

A several years after Bacchus, what could have driven Caravaggio to paint Amor Vincit Omnia for the artistic collector the nobleman, when he was at last growing almost respectable with prestigious ecclesiastical projects? This profane pagan god resurrects the erotic challenges of his initial works but in a increasingly intense, unsettling manner. Half a century later, its hidden meaning seemed clear: it was a portrait of Caravaggio's lover. A English traveller saw the painting in about the mid-seventeenth century and was told its figure has "the physique and countenance of [Caravaggio's|his] own youth or assistant that slept with him". The name of this adolescent was Francesco.

The painter had been dead for about 40 annums when this account was documented.