🔗 Share this article

A young lad screams as his skull is firmly gripped, a massive digit pressing into his cheek as his parent's mighty palm holds him by the neck. This moment from Abraham's Sacrifice appears in the Uffizi Gallery, evoking unease through the artist's chilling portrayal of the tormented youth from the biblical account. It seems as if Abraham, instructed by God to sacrifice his son, could break his neck with a solitary twist. However the father's chosen method involves the silvery grey blade he holds in his other palm, prepared to cut Isaac's throat. One definite element remains – whoever posed as Isaac for this breathtaking work demonstrated remarkable expressive ability. Within exists not just fear, shock and begging in his darkened eyes but also profound sorrow that a protector could abandon him so utterly.

The artist took a well-known biblical story and transformed it so fresh and raw that its terrors appeared to happen right in view of you

Viewing before the painting, observers identify this as a real face, an precise record of a adolescent model, because the identical boy – identifiable by his tousled locks and nearly black eyes – features in several additional works by the master. In each case, that highly expressive visage dominates the composition. In John the Baptist, he gazes playfully from the shadows while holding a ram. In Victorious Cupid, he grins with a toughness learned on the city's streets, his black plumed wings sinister, a naked child running chaos in a well-to-do residence.

Amor Vincit Omnia, currently exhibited at a London gallery, constitutes one of the most embarrassing artworks ever painted. Viewers feel completely disoriented looking at it. The god of love, whose darts inspire people with often agonizing longing, is shown as a extremely tangible, brightly illuminated unclothed form, straddling toppled-over objects that include stringed devices, a music score, metal armor and an builder's T-square. This heap of possessions resembles, deliberately, the geometric and construction gear scattered across the floor in the German master's print Melencolia I – except in this case, the gloomy disorder is caused by this smirking Cupid and the turmoil he can unleash.

"Love looks not with the eyes, but with the soul, / And thus is winged Cupid depicted blind," wrote the Bard, just before this work was produced around 1601. But the painter's Cupid is not unseeing. He stares straight at you. That countenance – sardonic and rosy-faced, staring with bold confidence as he struts naked – is the identical one that screams in fear in The Sacrifice of Isaac.

As Michelangelo Merisi da Caravaggio painted his three images of the same unusual-appearing youth in Rome at the dawn of the 17th century, he was the highly celebrated sacred artist in a city enflamed by Catholic renewal. Abraham's Offering demonstrates why he was commissioned to decorate churches: he could adopt a biblical story that had been portrayed numerous times previously and make it so fresh, so unfiltered and visceral that the terror seemed to be happening directly before you.

Yet there was a different aspect to Caravaggio, apparent as soon as he arrived in Rome in the cold season that ended 1592, as a painter in his early twenties with no mentor or supporter in the city, only skill and audacity. The majority of the works with which he captured the sacred city's eye were anything but holy. That may be the absolute earliest resides in the UK's art museum. A youth opens his crimson mouth in a scream of pain: while reaching out his dirty digits for a fruit, he has rather been bitten. Boy Bitten By a Lizard is eroticism amid poverty: observers can discern the painter's gloomy chamber reflected in the murky liquid of the transparent container.

The boy sports a rose-colored flower in his coiffure – a symbol of the sex commerce in Renaissance art. Northern Italian artists such as Titian and Palma Vecchio portrayed courtesans grasping flowers and, in a painting destroyed in the second world war but documented through photographs, the master portrayed a famous female prostitute, holding a posy to her bosom. The message of all these botanical signifiers is clear: sex for purchase.

What are we to make of the artist's erotic depictions of boys – and of a particular boy in specific? It is a inquiry that has divided his commentators since he achieved mega-fame in the 1980s. The complicated historical reality is that the painter was not the queer hero that, for instance, Derek Jarman presented on screen in his twentieth-century movie about the artist, nor so completely pious that, as some artistic historians improbably assert, his Youth Holding Fruit is actually a portrait of Christ.

His early works do make explicit sexual suggestions, or even offers. It's as if the painter, then a penniless youthful artist, aligned with the city's prostitutes, offering himself to survive. In the Florentine gallery, with this idea in mind, observers might turn to another early work, the 1596 masterpiece the god of wine, in which the deity of alcohol stares calmly at the spectator as he starts to undo the dark sash of his garment.

A several years after the wine deity, what could have driven the artist to create Amor Vincit Omnia for the art collector the nobleman, when he was at last growing almost established with prestigious ecclesiastical projects? This unholy non-Christian deity revives the erotic challenges of his early paintings but in a increasingly powerful, uneasy way. Fifty years afterwards, its secret seemed clear: it was a representation of Caravaggio's lover. A British visitor saw Victorious Cupid in about the mid-seventeenth century and was informed its figure has "the physique and countenance of [Caravaggio's|his] owne boy or servant that slept with him". The name of this boy was Francesco.

The painter had been dead for about forty years when this account was recorded.