Fiorentino's fourth birthday came around sooner than Leonardo would have liked. He woke up that morning in a cold sweat, shaken by a dream of contorted Templars standing over his son's hooded body, and with no idea if it was truly a dream or a vision of the future.

Beside him, Fee's face was pressed into the pillow, his hair sticking up in all directions as he slept. His bottom lip was jutting out and Leonardo found himself mesmerised for a moment; the blend of love and affection he felt for his son was enough to calm his fears.

"Fee," he said softly, rousing the boy with a gentle shake of his shoulder; "Wake up, Fee. Buon compleanno."

All he got in return was a displeased grumble, and Fiorentino's face being pressed further into the pillow. The artist laughed as he bounced to his feet. It was rare that Fee refused to wake up, but whenever it did happen usually a walk was enough to cajole him.

"Come, come," Leonardo chuckled, plucking the boy from the bed; "Breakfast and a walk are in order, I think. You and I can celebrate by looking at some more buildings, no?"

They had been in Venice for a few months – enough time to settle in, meet the assistants Leonardo's friendly nobleman had hired. Fiorentino had even made friends with the little girl that lived down the road, but, being a shy boy, it was a slow bond, and the girl's mother would often chuckle to the artist that it was more like an early courtship, so chivalrous was Fee's nature.

Unsurprisingly, after Leonardo had sent the letters, Magdalena was the first to have replied. It was perhaps the most detailed description he had ever had of his old workshop, now apparently 'neglected and stagnate, with cobwebs where art used to hang.' The woman's writings were like a muted hysteria, and a pang of anguish went through him when he thought how deluded she must have been to still believe herself in love with him.

Fillipa had been a few days after Magdalena, and Laura was last. The latter had given birth to a healthy baby girl beforehand, so most of her letter was about that, whereas Fillipa's was about her son's own apathy now that Fiorentino had left. They had been close, she decided, behind the scenes of their indifference towards each other.

"Do you know why this birthday is important, Fee?" the artist asked as he put their breakfast on the table, stuffed with basic sketches, and placed at the farthest wall so they could see the workshop. The flying machine was proudly strung up to the ceiling in the little alcove to the left, where Leonardo had put shelves and stuffed them with books, while around them lay unfinished paintings, rudimentary designs for strange devices, or the odd standing statuette that was to serve as a sort of makeshift model.

"Ezio. Assassins," the child's mouth was full of cheese as he spoke. He had been briefed on numerous occasions what was planned for him, but without any reason to fear he didn't anticipate it as much as Leonardo. There was no apprehension in his voice.

Then again, there was no understanding.

"Please swallow before you speak, Fee," Leonardo admonished, and then; "But you are right. This birthday is the last birthday before your training begins."

Fiorentino looked up at him as he took a bite of bread. His cheeks bulged, and Leonardo found himself smiling despite the tense atmosphere.

"Listen to me, Fiorentino. I must tell you something now that I haven't told you before."

He was gifted with his son's instant attention, perhaps because the tone of his voice was so sombre, or perhaps because the boy never seemed to disobey. It was rare to have a child so willing to accept their parent's rule.

"What the assassini teach you…much of it will seem strange, perhaps even scare you, but you must learn it all, do you understand?"

Brown eyes were fraught with confusion. Fiorentino placed the half-eaten bread back on his plate – a brass thing, meant only for temporary use until Leonardo's assistants washed their new tableware – and cocked his head to one side, as though his father was something to be studied.

"Do…do…" he was struggling with the words, mouth working like he was chewing something too strong; "Do assassini…hurt?"

"Do they hurt…you?"

"No," Fee shook his head, "People?"

Leonardo fell silent. How could he tell his son of the killings, the things he was expected to carry out one day? Fiorentino was an innocent despite his mysterious start in life, and to shatter that with the thought of spilling blood…

"Fee..." he sighed; "You know the bodies in the back of the shop, yes? The ones I tell you not to go near?"

"Research ca-cadavers?"

"Yes – the cadavers." Leonardo took a deep breath, "Sometimes, people need to die for the greater good. Those cadavers help me understand the body's inner workings, and from that I can understand how to help dottores cure people's ills. But I would never have been able to do that if those cadavers hadn't been given to me; if people hadn't died."

"But…I…" Fiorentino's eyes moistened, but the artist went on.

"What Ezio does is much the same, but in a different way. He makes sure those who hurt us can never do it again. That's what the Assassin order does."

There was silence for a moment. Fee pushed his plate away with sad eyes, comprehending what he was being told but not liking any of it, before he looked up and fixed Leonardo with a trusting gaze.

"I'm scared."

Leonardo instantly got up from his seat, food untouched, and went to crouch beside his son, who buried his face the familiar clothed shoulder and allowed himself to be lifted. He was getting heavier, the artist noted, but not so heavy that he was impossible to pick up.

"Don't be, Fee. Ezio will keep you safe, and the skills you gain will help you. I wish it were not so – perhaps it would have been better if you were given to someone else."

He had never meant to say it aloud, but Fiorentino seemed shocked at the very idea of being given to someone else. His arms tightened around his father's neck as though laying claim to him, making him realise just how much their bond meant to the boy in his arms.

"No. Love you, Maestro."

"And I love you, Fifi."

"Not Fifi!" Fiorentino raised his head to look at his father, a good-natured smile on his face.

"Truly?" the artist faked surprise; "You're not a girl?"

"No!"

The child laughed; the first laugh Leonardo had heard all morning. Breakfast was a pleasant affair afterwards, and when they took to the town for their walk, it was in a more festive mood, one that suited the day's special status.

It was when they came to a small child crying that Leonardo made them stop. The girl was older than Fee – about seven, maybe eight – and her hair was dirty, her eyes red and bloodshot. The artist was swayed by her horrible state.

"What is it, little one? What's your name?"

She did not answer him, but instead pointed up at a small bird that had flown into one of the pillars that lined the Venetian canals. On its leg, there was a note.

A disobedient carrier pigeon, the artist thought as he peered at it, Banes of modern existence. Ah, how can I help? It's much too high.

Around them, people either walked passed or stopped to inspect the crying child, looking up as Leonardo did to the small pigeon in the pillar. It was Fiorentino's tugging at the artist's sleeve that snatched his attention back.

"Assassini!" he said, which caused Leonardo to drop down to one knee and instantly shush him.

"Not here, Fee. We mustn't speak of the assassins in public."

"Help!" he pointed at the pillar and then his feet, trying to convey through hand gestures what he was too young to say himself; "Help!"

Leonardo gave him a blank stare, and then realised what he was saying. Without delay the artist lifted his son up, careful to let him balance as he put his heels on the palm of his father's hands and reached up, snatching the bird by the leg for he was too small to reach anything else. The people were in stunned silence as Fee was brought back down. It was not for the random act of kindness that they were amazed, but for the fact that he hadn't fallen, that his balance was so precise for someone so young.

The girl had stopped crying long enough to take the bird from Fiorentino's proffered hand, and when she planted a grateful kiss on his cheeks a faint blush rose there. Leonardo had to suppress his laughter; Fee's shyness was one of his most adorable traits.

"Grazie," she smiled.

"Macché."

When they walked away from the girl and her troublesome pet, Fiorentino reached up and gripped Leonardo's hand, smiling at him as he said; "Help. Help without hurting."

The artist said nothing.