What was the dark-feathered deity of desire? What insights this masterpiece reveals about the rogue artist

A young boy cries out as his skull is forcefully held, a massive thumb digging into his cheek as his father's mighty hand holds him by the throat. This scene from Abraham's Sacrifice visits the Uffizi Gallery, evoking distress through Caravaggio's harrowing rendition of the tormented youth from the biblical narrative. It appears as if Abraham, commanded by God to sacrifice his son, could break his spinal column with a solitary turn. Yet Abraham's preferred approach involves the metallic grey knife he holds in his remaining palm, prepared to slit the boy's throat. One definite element stands out – whomever posed as Isaac for this astonishing work displayed remarkable expressive ability. There exists not just fear, surprise and pleading in his darkened eyes but additionally profound grief that a protector could betray him so completely.

He took a familiar biblical story and transformed it so vibrant and visceral that its horrors appeared to happen right in view of you

Standing in front of the artwork, viewers recognize this as a actual countenance, an precise record of a young subject, because the same boy – identifiable by his disheveled locks and nearly black eyes – appears in several additional paintings by Caravaggio. In each case, that richly emotional face dominates the composition. In John the Baptist, he gazes mischievously from the darkness while embracing a ram. In Victorious Cupid, he grins with a hardness learned on Rome's alleys, his black plumed appendages demonic, a naked adolescent running riot in a well-to-do residence.

Victorious Cupid, currently exhibited at a British museum, represents one of the most embarrassing masterpieces ever created. Observers feel totally disoriented gazing at it. Cupid, whose darts fill people with frequently agonizing longing, is shown as a very tangible, brightly lit nude figure, straddling toppled-over objects that include stringed instruments, a music score, plate armour and an architect's T-square. This heap of items echoes, intentionally, the geometric and architectural gear scattered across the ground in Albrecht Dürer's print Melencolia I – except in this case, the gloomy mess is caused by this smirking deity and the mayhem he can unleash.

"Love looks not with the vision, but with the mind, / And therefore is winged Love painted sightless," penned Shakespeare, shortly prior to this painting was created around 1601. But Caravaggio's Cupid is not unseeing. He stares directly at you. That countenance – sardonic and rosy-faced, looking with bold assurance as he struts naked – is the same one that screams in terror in Abraham's Test.

When the Italian master created his three images of the identical distinctive-appearing kid in the Eternal City at the dawn of the seventeenth century, he was the most acclaimed sacred painter in a metropolis ignited by religious revival. Abraham's Offering reveals why he was commissioned to decorate churches: he could adopt a scriptural narrative that had been depicted many occasions before and make it so fresh, so unfiltered and visceral that the terror seemed to be happening directly before you.

However there was a different side to Caravaggio, evident as soon as he arrived in Rome in the winter that concluded 1592, as a artist in his early twenties with no mentor or supporter in the city, just skill and audacity. Most of the paintings with which he captured the sacred metropolis's eye were anything but devout. That may be the absolute first hangs in London's National Gallery. A youth opens his crimson mouth in a scream of agony: while reaching out his filthy fingers for a fruit, he has rather been bitten. Youth Bitten by a Reptile is sensuality amid squalor: observers can see the painter's gloomy room mirrored in the murky waters of the glass vase.

The boy wears a pink flower in his coiffure – a emblem of the sex commerce in Renaissance art. Northern Italian painters such as Tiziano and Jacopo Palma depicted prostitutes grasping flowers and, in a painting destroyed in the second world war but documented through images, Caravaggio represented a famous female prostitute, holding a bouquet to her chest. The message of all these botanical signifiers is obvious: intimacy for purchase.

How are we to make of Caravaggio's erotic portrayals of youths – and of a particular adolescent in particular? It is a inquiry that has split his commentators since he gained widespread recognition in the twentieth century. The complicated historical truth is that the artist was neither the queer hero that, for instance, the filmmaker presented on film in his twentieth-century film Caravaggio, nor so completely pious that, as certain art scholars unbelievably claim, his Youth Holding Fruit is in fact a portrait of Christ.

His early paintings indeed offer overt erotic suggestions, or even offers. It's as if the painter, then a penniless young creator, aligned with the city's sex workers, selling himself to live. In the Uffizi, with this idea in consideration, viewers might turn to an additional initial creation, the sixteenth-century masterpiece Bacchus, in which the god of wine gazes coolly at you as he starts to undo the black sash of his robe.

A several years after Bacchus, what could have driven the artist to paint Victorious Cupid for the art collector the nobleman, when he was finally becoming almost respectable with important church commissions? This profane non-Christian deity resurrects the sexual challenges of his early works but in a increasingly intense, uneasy way. Fifty years later, its hidden meaning seemed clear: it was a representation of the painter's companion. A British visitor viewed the painting in about the mid-seventeenth century and was informed its subject has "the physique and countenance of [Caravaggio's|his] own boy or servant that laid with him". The identity of this adolescent was Cecco.

The artist had been dead for about 40 years when this story was recorded.