What was Caravaggio's dark-feathered god of love? What insights this masterpiece reveals about the rebellious artist

A young boy screams as his head is firmly held, a massive digit digging into his cheek as his father's mighty palm grasps him by the throat. This scene from The Sacrifice of Isaac visits the Uffizi Gallery, evoking distress through Caravaggio's chilling portrayal of the tormented youth from the biblical account. The painting seems as if Abraham, commanded by the Divine to sacrifice his son, could snap his spinal column with a single twist. However Abraham's chosen approach involves the silvery steel knife he grips in his other hand, ready to cut the boy's throat. One certain aspect remains – whoever posed as the sacrifice for this breathtaking piece displayed remarkable expressive skill. There exists not just dread, surprise and pleading in his shadowed gaze but additionally deep sorrow that a guardian could abandon him so completely.

The artist adopted a familiar scriptural story and transformed it so vibrant and visceral that its horrors appeared to unfold right in front of you

Standing in front of the artwork, viewers recognize this as a real countenance, an precise record of a young model, because the same youth – identifiable by his disheveled locks and nearly dark eyes – features in two additional paintings by the master. In every case, that highly expressive face commands the scene. In John the Baptist, he peers playfully from the darkness while embracing a lamb. In Amor Vincit Omnia, he grins with a hardness acquired on the city's alleys, his dark feathery appendages demonic, a naked child running chaos in a affluent residence.

Amor Vincit Omnia, presently displayed at a British gallery, constitutes one of the most embarrassing artworks ever created. Observers feel totally disoriented gazing at it. The god of love, whose arrows fill people with often painful longing, is shown as a very tangible, vividly lit nude figure, standing over toppled-over items that include musical instruments, a musical score, plate armor and an architect's ruler. This pile of possessions resembles, deliberately, the mathematical and construction gear scattered across the ground in the German master's engraving Melencolia I – save here, the melancholic disorder is caused by this grinning deity and the turmoil he can unleash.

"Affection sees not with the eyes, but with the mind, / And therefore is feathered Cupid depicted sightless," penned Shakespeare, shortly prior to this work was produced around the early 1600s. But the painter's Cupid is not blind. He stares straight at you. That face – ironic and ruddy-cheeked, staring with bold assurance as he poses unclothed – is the same one that screams in terror in Abraham's Test.

As the Italian master created his three portrayals of the identical unusual-looking youth in the Eternal City at the start of the 17th century, he was the highly acclaimed religious artist in a city ignited by Catholic renewal. The Sacrifice of Isaac reveals why he was commissioned to decorate churches: he could take a scriptural narrative that had been depicted numerous times before and render it so new, so raw and physical that the horror seemed to be happening directly before you.

However there existed another aspect to Caravaggio, evident as quickly as he came in Rome in the winter that ended 1592, as a artist in his early 20s with no mentor or supporter in the city, just skill and boldness. The majority of the paintings with which he caught the holy metropolis's eye were anything but devout. That may be the absolute earliest resides in London's National Gallery. A young man opens his crimson lips in a scream of agony: while stretching out his filthy fingers for a fruit, he has rather been attacked. Boy Bitten By a Lizard is eroticism amid poverty: viewers can see the painter's dismal room mirrored in the murky liquid of the transparent vase.

The adolescent sports a rose-colored flower in his coiffure – a emblem of the sex trade in early modern art. Northern Italian painters such as Titian and Palma Vecchio portrayed courtesans grasping flowers and, in a work destroyed in the WWII but documented through images, the master portrayed a famous woman prostitute, holding a posy to her chest. The meaning of all these floral signifiers is obvious: sex for purchase.

How are we to interpret of Caravaggio's erotic depictions of youths – and of a particular adolescent in particular? It is a question that has split his commentators since he gained widespread recognition in the 1980s. The complicated past reality is that the painter was not the queer hero that, for instance, Derek Jarman put on screen in his 1986 movie about the artist, nor so completely pious that, as certain art scholars unbelievably claim, his Boy With a Basket of Fruit is actually a portrait of Christ.

His initial paintings indeed offer explicit erotic suggestions, or including offers. It's as if Caravaggio, then a destitute young artist, identified with Rome's prostitutes, offering himself to live. In the Florentine gallery, with this idea in mind, observers might look to an additional early work, the 1596 masterpiece Bacchus, in which the deity of alcohol stares calmly at you as he starts to untie the black ribbon of his robe.

A few annums after Bacchus, what could have driven the artist to create Victorious Cupid for the art collector Vincenzo Giustiniani, when he was at last growing nearly established with important ecclesiastical commissions? This profane pagan god revives the erotic provocations of his early works but in a more intense, uneasy way. Half a century afterwards, its hidden meaning seemed clear: it was a representation of Caravaggio'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] owne boy or assistant that slept with him". The identity of this adolescent was Cecco.

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