Painting Mona Lisa. Jeanne Kalogridis

He had hurt him in his most vulnerable moment, and when Giuliano had said, I love you, Lorenzo … Please don’t make me choose, Lorenzo had been cruel. Had turned him away, without help – the one thing he owed Giuliano most of all.

      How could he explain to the others that he could never leave his younger brother behind? How could he explain the responsibility he felt for Giuliano, who had lost his father so young and had always looked to Lorenzo for guidance? How could he explain the promise he had made to his father on the latter’s deathbed? They were all too concerned with the safety of Lorenzo il Magnifico, whom they considered to be the greatest man in Florence, but they were wrong, all of them.

      Lorenzo was pushed behind the thick, heavy doors of the sacristy. They slammed shut after someone ventured out to fetch the wounded Nori.

      Inside, the airless, windowless chamber smelled of sacrificial wine and the dust that had settled on the priests’ vestments. Lorenzo grabbed each man who had pushed him to safety; he studied each face, and was each time disappointed. The greatest man in Florence was not here.

      He thought of Baroncelli’s great curving knife and of the bright blood on Francesco de’ Pazzi’s and tunic. The images propelled him to move for the doors, with the intention of flinging them open and going back to rescue his brother. But della Stuffa sensed his intention, and immediately pressed his body against the exit. Old Michelozzo joined him, then Antonio Ridolfo; the weight of the three men held the doors fast shut. Lorenzo was pushed to the outer edge of the engraved brass. There was a grimness in their expressions, an unspoken, unspeakable knowledge that Lorenzo could not and would not accept.

      Hysterically, he pounded on the cold brass until his fists ached – and then he continued to pound until they bled. The scholar Angelo Poliziano struggled to wrap a piece of wool, torn from his own mantle, around the bleeding cut on Lorenzo’s neck. Lorenzo tried to push the distraction away, but Poliziano persisted until the wound was bound tight.

      All the while, Lorenzo did not cease his frantic efforts. ‘My brother!’ he cried shrilly, and would not be moved by those who came to comfort him, would not be stilled or quieted. ‘I must go and find him! My brother! Where is my brother …?’

       VII

      As he stood beside Bernardo Bandini Baroncelli in the Duomo, Giuliano’s head was bowed. He was not a man who usually prayed: he had long ago come to the conclusion that religion was the invention of men, and that there could be no certainty when it came to the question of God. Unfortunately, the Church’s earthly power demanded that he keep up appearances, show the required reverence, make the required gestures.

      But this morning, his desperation provoked him to speak silently to God, should He be there to listen. Giuliano silently confessed that over the years, he had been callous towards his lovers. He had abused his physical handsomeness and used it to dally with their affections; he had taken their adoration for granted and often dismissed them thoughtlessly. Now he was filled with remorse; he saw clearly the divine irony in the fact that he now had to suffer to have the one he truly loved. Even worse, his love caused her suffering.

      He asked that God soften Lorenzo’s heart, or the Pope’s, or do whatever was necessary so that her misery might end.

      God answered his prayer in unexpected fashion. The subtlest sound of metal sliding against leather made him glance upwards.

      To his right, Baroncelli finished withdrawing his knife from its sheath, and by the time Giuliano had turned his head to stare at the weapon in amazement, Baroncelli was ready to strike.

      The act occurred too swiftly for Giuliano to be frightened.

      Instinctively, he backed away. A body pressed into him, so firm and so fast, there could be no doubt its owner was part of the conspiracy. Giuliano glimpsed a man dressed in the robes of a penitent – and then gasped at the cold, burning sensation of steel sliding into his back, into his right kidney.

      He had been terribly wounded. He was surrounded by assassins, and was about to die.

      The realizations did not distress him as much as the fact that he was trapped and unable to warn Lorenzo. Surely his brother would be the next target.

      ‘Lorenzo,’ he said emphatically, as Baroncelli’s knife came flashing down, the blade reflecting a hundred tiny flames from the candles on the altar. But his utterance was drowned out by Baroncelli’s panicked, nonsensical cry: ‘Here, traitor!’

      The blow caught Giuliano between his uppermost pair of ribs. There came the dull crack of bone, and a second spasm of pain so intense, so impossible, it left him breathless.

      Baroncelli’s clean-shaven face, so close to Giuliano’s own, was gleaming with sweat. He grunted with effort as he withdrew the knife from Giuliano’s chest; it came out whistling. Giuliano fought to draw another breath, to call out Lorenzo’s name again; it came out less audible than a whisper.

      In the space of a heartbeat, Giuliano remembered with exquisite clarity an incident from childhood: at age six, he had gone with Lorenzo and two of his older sisters, Nannina and Bianca, for a picnic on the shores of the Arno. Attended by a Circassian slave woman, they had travelled by carriage across the Ponte Vecchio, the bridge built a millennium before by the Romans. Nannina had been captivated by the goldsmiths’ shops that lined the bridge; soon to be married, she was already interested in womanly things.

      Lorenzo had been restless and glum. He had just begun to take on Medici responsibilities; the year before, he had begun receiving letters asking for his patronage, and their father, Piero, had already sent his eldest son to Milan and Rome on politically-motivated trips. He was a homely boy, with wide-set slanting eyes, a jutting jaw, and soft brown hair that fell in neatly-trimmed fringe across a pale, low forehead; yet the sensitive intelligence that shone in those eyes made him oddly attractive.

      They made their way to the pastoral neighbourhood of Santo Spirito. Giuliano recalled tall trees, and a sweeping grass lawn that sloped down to the placid river. There, the slave woman set a linen cloth on the ground and brought out food for the children. It was late spring: warm with a few lazy clouds, though the day before it had rained. The River Arno was quicksilver when the sun struck it, leaden when it did not.

      Lorenzo’s sullenness that day had made Giuliano sad. It seemed to him that their father was too intent on making Lorenzo an adult before his time. So, to make him laugh, Giuliano had run down to the riverbank, gleefully ignoring the slave’s outraged threats, and stomped, splashing, into the water fully clothed.

      His antics worked; Lorenzo followed him in laughing, tunic, mantle, slippers and all. By this time, Nannina, Bianca, and the slave were all shouting their disapproval. Lorenzo ignored them. He was a strong swimmer, and soon made his way quite a distance from the shore, then dove beneath the waters.

      Giuliano followed tentatively, but being younger, fell behind. He watched as Lorenzo took a great gulp of air and disappeared beneath the grey surface. When he did not reappear immediately, Giuliano treaded water and laughed, expecting his brother to swim beneath him and grasp his foot at any moment.

      Seconds passed. Giuliano’s laughter turned to silence, then fear – then he began calling for his brother. On the shore, the women – unable to enter the water, because of their heavy skirts – began to cry out in panic.

      Giuliano was only a child. He had not yet overcome his fear of diving beneath the water, yet love for his brother drove him to suck in a deep breath and submerge himself. The silence there astonished him; he opened his eyes and peered in the direction where Lorenzo had been.

      The river was muddy from the previous day’s rains; Giuliano’s eyes stung as he searched. He could see nothing but a large, irregular dark shape some distance away from him, deep beneath the waters. It was not human – not Lorenzo – but it was all that was visible, and instinct told him to approach it. He surfaced, drew in more air, then compelled himself to dive down again: there, the length of three tall men beneath the surface, lay the craggy limbs of a fallen tree.

      Giuliano’s