What was the black-winged god of desire? What insights this masterwork uncovers about the rogue artist

The young lad cries out while his head is forcefully gripped, a massive thumb pressing into his cheek as his father's powerful hand holds him by the neck. This moment from The Sacrifice of Isaac visits the Uffizi Gallery, creating unease through Caravaggio's harrowing rendition of the tormented child from the biblical account. It seems as if Abraham, instructed by the Divine to sacrifice his son, could break his neck with a single twist. However the father's preferred method involves the metallic grey knife he grips in his remaining palm, ready to cut the boy's throat. One certain aspect remains – whoever posed as Isaac for this breathtaking work demonstrated remarkable expressive skill. Within exists not only fear, surprise and pleading in his shadowed eyes but additionally profound grief that a protector could betray him so completely.

The artist took a familiar scriptural story and transformed it so vibrant and raw that its terrors appeared to happen right in view of you

Viewing in front of the artwork, observers recognize this as a real face, an accurate depiction of a adolescent subject, because the same youth – recognizable by his disheveled hair and almost dark pupils – features in several other works by the master. In each instance, that richly expressive visage commands the scene. In Youth With a Ram, he peers mischievously from the darkness while embracing a ram. In Amor Vincit Omnia, he grins with a toughness learned on Rome's streets, his black plumed appendages demonic, a naked child creating riot in a affluent dwelling.

Victorious Cupid, currently exhibited at a British museum, represents one of the most embarrassing masterpieces ever created. Viewers feel completely disoriented gazing at it. Cupid, whose arrows fill people with frequently painful longing, is shown as a extremely tangible, vividly lit unclothed figure, standing over toppled-over objects that include musical devices, a musical manuscript, plate armor and an builder's ruler. This heap of items resembles, deliberately, the geometric and construction gear scattered across the floor in Albrecht Dürer's print Melancholy – except in this case, the melancholic disorder is created by this grinning Cupid and the turmoil he can unleash.

"Affection looks not with the eyes, but with the soul, / And thus is winged Cupid depicted blind," penned the Bard, shortly prior to this work was produced around 1601. But Caravaggio's god is not unseeing. He stares straight at you. That countenance – sardonic and ruddy-cheeked, staring with brazen confidence as he struts unclothed – is the same one that screams in terror in The Sacrifice of Isaac.

When Michelangelo Merisi da Caravaggio painted his multiple images of the identical unusual-looking youth in the Eternal City at the dawn of the seventeenth century, he was the highly acclaimed religious painter in a city ignited by Catholic renewal. The Sacrifice of Isaac demonstrates why he was sought to adorn sanctuaries: he could take a biblical narrative that had been depicted many occasions previously and make it so fresh, so unfiltered and visceral that the terror seemed to be occurring directly in front of you.

Yet there was another aspect to the artist, apparent as quickly as he came in the capital in the cold season that ended the sixteenth century, as a artist in his initial twenties with no teacher or supporter in the city, only skill and audacity. The majority of the works with which he captured the sacred metropolis's attention were anything but holy. What may be the absolute first hangs in the UK's art museum. A young man opens his crimson mouth in a yell of pain: while reaching out his filthy fingers for a cherry, he has rather been attacked. Youth Bitten by a Reptile is eroticism amid poverty: viewers can see the painter's gloomy room reflected in the cloudy liquid of the glass container.

The adolescent sports a rose-colored blossom in his coiffure – a symbol of the erotic trade in early modern painting. Venetian painters such as Titian and Palma Vecchio depicted courtesans grasping blooms and, in a painting lost in the second world war but known through photographs, Caravaggio represented a famous woman prostitute, clutching a bouquet to her chest. The message of all these botanical signifiers is clear: sex for sale.

What are we to make of the artist's erotic portrayals of youths – and of one boy in particular? It is a inquiry that has split his interpreters since he gained mega-fame in the twentieth century. The complicated historical reality is that the painter was neither the homosexual hero that, for instance, Derek Jarman presented on film in his 1986 film about the artist, nor so entirely pious that, as some artistic historians unbelievably assert, his Youth Holding Fruit is in fact a likeness of Christ.

His initial works indeed offer explicit sexual suggestions, or even offers. It's as if Caravaggio, then a destitute youthful artist, identified with Rome's prostitutes, selling himself to live. In the Uffizi, with this thought in consideration, viewers might turn to an additional early creation, the sixteenth-century masterpiece the god of wine, in which the god of alcohol gazes calmly at the spectator as he begins to undo the black sash of his garment.

A few annums following Bacchus, what could have driven Caravaggio to paint Amor Vincit Omnia for the artistic patron the nobleman, when he was finally becoming nearly established with prestigious ecclesiastical projects? This profane non-Christian god revives the erotic challenges of his initial paintings but in a more powerful, uneasy way. Half a century afterwards, its secret seemed obvious: it was a representation of Caravaggio's lover. A English visitor saw Victorious Cupid in about the mid-seventeenth century and was told its figure has "the physique and countenance of [Caravaggio's|his] owne youth or servant that laid with him". The identity of this adolescent was Cecco.

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