What exactly was the black-winged deity of desire? What secrets this masterpiece reveals about the rogue genius

The young boy screams as his skull is firmly gripped, a large digit pressing into his face as his parent's mighty palm holds him by the neck. That scene from The Sacrifice of Isaac visits the Uffizi Gallery, creating unease through Caravaggio's chilling portrayal of the suffering youth from the scriptural narrative. The painting seems as if the patriarch, commanded by God to sacrifice his offspring, could break his neck with a solitary twist. Yet Abraham's chosen approach involves the metallic steel knife he holds in his remaining hand, ready to cut Isaac's throat. One definite aspect remains – whomever modeled as Isaac for this astonishing piece demonstrated extraordinary expressive skill. There exists not just dread, surprise and begging in his shadowed eyes but additionally deep sorrow that a protector could betray him so completely.

The artist adopted a familiar biblical tale and transformed it so vibrant and raw that its horrors appeared to unfold right in front of you

Standing before the artwork, observers recognize this as a actual countenance, an precise depiction of a young subject, because the identical boy – recognizable by his disheveled hair and almost dark pupils – features in several other works by Caravaggio. In every instance, that highly emotional face commands the scene. In Youth With a Ram, he peers playfully from the darkness while embracing a ram. In Amor Vincit Omnia, he smirks with a hardness learned on the city's alleys, his black feathery wings sinister, a naked child running riot in a well-to-do dwelling.

Amor Vincit Omnia, currently exhibited at a British museum, constitutes one of the most embarrassing masterpieces ever created. Observers feel completely disoriented looking at it. The god of love, whose arrows fill people with frequently agonizing longing, is portrayed as a extremely tangible, vividly lit nude form, straddling toppled-over items that comprise musical devices, a musical score, metal armor and an architect's ruler. This heap of items echoes, intentionally, the mathematical and construction equipment strewn across the floor in the German master's print Melencolia I – except in this case, the melancholic disorder is created by this grinning Cupid and the mayhem he can release.

"Affection sees not with the eyes, but with the soul, / And therefore is feathered Cupid painted sightless," wrote the Bard, shortly before this painting was produced around 1601. But the painter's Cupid is not unseeing. He gazes directly at the observer. That countenance – sardonic and rosy-cheeked, staring with bold assurance as he struts naked – is the same one that shrieks in terror in Abraham's Test.

As the Italian master created his three portrayals of the same unusual-appearing youth in the Eternal City at the start of the seventeenth century, he was the highly celebrated religious artist in a city enflamed by Catholic revival. The Sacrifice of Isaac demonstrates why he was sought to adorn sanctuaries: he could adopt a biblical narrative that had been depicted many times before and render it so new, so raw and physical that the terror seemed to be happening directly in front of you.

Yet there was a different aspect to the artist, evident as quickly as he arrived in Rome in the cold season that concluded 1592, as a artist in his initial twenties with no mentor or patron in the urban center, only skill and boldness. The majority of the works with which he caught the sacred metropolis's eye were anything but devout. What may be the absolute first resides in the UK's National Gallery. A youth opens his red lips in a yell of agony: while stretching out his dirty digits for a cherry, he has rather been attacked. Youth Bitten by a Reptile is sensuality amid poverty: viewers can see Caravaggio's gloomy room mirrored in the murky liquid of the glass container.

The boy wears a rose-colored blossom in his hair – a symbol of the sex commerce in Renaissance painting. Northern Italian artists such as Tiziano and Jacopo Palma depicted courtesans grasping blooms and, in a work lost in the WWII but known through images, Caravaggio portrayed a renowned female prostitute, holding a posy to her bosom. The meaning of all these floral indicators is obvious: sex for sale.

What are we to interpret of the artist's sensual portrayals of youths – and of a particular boy in particular? It is a question that has divided his interpreters ever since he gained mega-fame in the 1980s. The complex historical reality is that the painter was not the queer hero that, for instance, the filmmaker presented on film in his twentieth-century movie Caravaggio, nor so entirely devout that, as certain artistic historians improbably assert, his Boy With a Basket of Fruit is actually a likeness of Christ.

His early paintings do make explicit erotic suggestions, or even propositions. It's as if the painter, then a destitute youthful creator, aligned with the city's prostitutes, offering himself to survive. In the Uffizi, with this idea in consideration, observers might turn to another initial work, the 1596 masterwork Bacchus, in which the deity of alcohol stares coolly at you as he starts to undo the black ribbon of his robe.

A few years following Bacchus, what could have motivated Caravaggio to create Amor Vincit Omnia for the artistic patron the nobleman, when he was at last growing almost respectable with prestigious church projects? This unholy pagan deity resurrects the erotic provocations of his initial paintings but in a increasingly powerful, uneasy manner. Fifty years later, its secret seemed clear: it was a portrait of the painter's companion. A British visitor saw the painting in about the mid-seventeenth century and was informed its subject has "the body & face of [Caravaggio's|his] own boy or servant that laid with him". The identity of this boy was Cecco.

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