Who was Caravaggio's dark-feathered god of love? The secrets this masterpiece reveals about the rebellious artist

A young lad screams while his skull is forcefully gripped, a massive thumb digging into his face as his parent's mighty palm grasps him by the throat. That scene from Abraham's Sacrifice appears in the Florentine museum, creating distress through the artist's harrowing rendition of the suffering youth from the biblical narrative. It seems as if the patriarch, instructed by the Divine to kill his offspring, could break his neck with a single turn. However the father's preferred method involves the silvery grey blade he grips in his remaining hand, ready to cut the boy's throat. A definite aspect remains – whoever posed as the sacrifice for this astonishing work displayed extraordinary expressive ability. There exists not just fear, shock and pleading in his shadowed gaze but also deep sorrow that a protector could betray him so utterly.

He adopted a familiar biblical story and made it so vibrant and visceral that its horrors appeared to unfold right in view of the viewer

Viewing in front of the painting, observers identify this as a actual face, an accurate record of a adolescent subject, because the identical youth – identifiable by his tousled hair and almost dark eyes – features in two additional paintings by the master. In every instance, that richly emotional face dominates the composition. In John the Baptist, he peers playfully from the darkness while holding a ram. In Victorious Cupid, he smirks with a hardness acquired on Rome's alleys, his dark plumed wings demonic, a unclothed adolescent running riot in a affluent residence.

Amor Vincit Omnia, currently displayed at a London gallery, constitutes one of the most embarrassing artworks ever created. Viewers feel totally unsettled gazing at it. Cupid, whose arrows fill people with often agonizing longing, is portrayed as a very tangible, vividly illuminated unclothed form, standing over toppled-over items that include stringed devices, a musical score, plate armor and an builder's T-square. This pile of items echoes, deliberately, the mathematical and architectural equipment strewn across the floor in Albrecht Dürer's print Melancholy – save here, the gloomy disorder is created by this smirking Cupid and the turmoil he can release.

"Love looks not with the vision, but with the soul, / And therefore is feathered Love depicted sightless," wrote the Bard, just prior to this work was created around 1601. But the painter's Cupid is not blind. He stares straight at you. That face – ironic and ruddy-cheeked, staring with bold confidence as he poses naked – is the same one that shrieks in terror in Abraham's Test.

As Michelangelo Merisi da Caravaggio created his multiple portrayals of the same distinctive-looking kid in the Eternal City at the dawn of the 17th century, he was the highly celebrated sacred painter in a city enflamed by religious revival. Abraham's Offering reveals why he was sought to adorn churches: he could adopt a biblical story that had been depicted many occasions before and make it so new, so unfiltered and physical that the terror seemed to be happening immediately before you.

Yet there existed another side to Caravaggio, evident as soon as he came in Rome in the winter that ended the sixteenth century, as a painter in his initial 20s with no mentor or patron in the urban center, just talent and boldness. The majority of the works with which he captured the sacred metropolis's attention were anything but devout. What may be the very earliest resides in London's National Gallery. A young man parts his red lips in a scream of agony: while stretching out his dirty digits for a cherry, he has instead been attacked. Boy Bitten By a Lizard is sensuality amid poverty: observers can see Caravaggio's gloomy chamber reflected in the murky waters of the glass vase.

The boy sports a pink blossom in his hair – a symbol of the sex commerce in Renaissance painting. Northern Italian painters such as Titian and Palma Vecchio portrayed courtesans grasping flowers and, in a work destroyed in the WWII but known through images, the master portrayed a renowned woman prostitute, holding a bouquet to her chest. The message of all these botanical indicators is obvious: sex for purchase.

How are we to interpret of Caravaggio's sensual depictions of youths – and of a particular boy in particular? It is a inquiry that has split his commentators since he achieved widespread recognition in the twentieth century. The complex historical truth is that the artist was not the homosexual hero that, for example, Derek Jarman presented on screen in his 1986 film about the artist, nor so entirely devout that, as certain art scholars unbelievably assert, his Boy With a Basket of Fruit is actually a portrait of Christ.

His initial works indeed make explicit sexual implications, or including offers. It's as if Caravaggio, then a penniless youthful creator, aligned with Rome's sex workers, offering himself to survive. In the Florentine gallery, with this thought in consideration, observers might turn to an additional initial work, the 1596 masterpiece the god of wine, in which the god of alcohol stares calmly at the spectator as he begins to undo the black sash of his robe.

A few years following Bacchus, what could have motivated the artist to create Amor Vincit Omnia for the artistic patron the nobleman, when he was at last growing almost established with prestigious ecclesiastical commissions? This unholy pagan god resurrects the sexual provocations of his early works but in a increasingly intense, unsettling way. Half a century later, its hidden meaning seemed clear: it was a portrait of the painter's companion. A British traveller viewed the painting in about the mid-seventeenth century and was informed its figure has "the body & face of [Caravaggio's|his] owne youth or servant that laid with him". The name of this adolescent was Cecco.

The painter had been dead for about 40 annums when this story was recorded.