The rain stopped some time during Leonardo's studies.

Fillipa came and went, undeterred by the strange man's presence, and left the artist to his work. Every now and again he became aware of a high pitched giggling from inside the play pen, but then he came across another fascinating code and he was lost once more.

It was only when Vincenzo announced his arrival that the painter was brought out of his trance. He realised strong sunlight was washing over his workshop, and he hadn't heard Fiorentino's laugh in a very long while.

"Oh, there you are!" he greeted his assistant, a young man who wore his brown hair in a dead-straight style, his clothes modest but strong and his mind alert, "Will you go and set up some dummies for my friend to practice on? The yard should do."

"Sì, Maestro. Will there be anything else?"

Waving him off, Leonardo took care not to look at the Codex page again. If he did, he ran the risk of going back into a trance, one he wouldn't come out of until he had unlocked the ancient secrets that little passage held. No. He had other things to do; things such as find out where Ezio and Fiorentino had gone.

The pair were not where he had left them the night before. The play pen was empty save a few toys, many of them well-chewed and still with sheens of spittle to decorate them, and Leonardo was quick to rove over where else in the shop they could have gone to. There were rooms above the workshop; a bedroom, a rudimentary bathroom, a small cupboard he had yet to fill with anything but failed paintings, and a smaller study, which he intended to convert into Fiorentino's bedroom when the boy was old enough.

Perhaps they went exploring? Leonardo thought as he made his way towards the stairs; Ezio hasn't been here many times, and Fee probably got restless in his pen. That must be it. That boy; if he could walk, I don't know how I would cope.

When he reached the second floor, he noticed all the doors were shut, save one. His bedroom door was ajar and he could make out through the tiny crack a figure, hooded head slouched forward in the chair he kept beside his bed, hands clasped together as though in prayer.

Leonardo pushed the door open gently. It moved forward without so much as a creak to reveal the room; Ezio had fallen asleep, upright in the chair, which was positioned beside a beige double-bed littered by leather-bound books, itself beside a small box where the artist kept his clothes. At the end of it was Fee's crib, but it looked empty, and Leonardo couldn't help the stab of panic that attacked his heart.

But when he looked up, he needn't have worried.

On the bed, nestled between the clutter, was Fiorentino. The boy's arms were raised up until they reached his face, and one of his hands was pressed to the bridge of his nose, his eyes shut. His head was turned to the side to face Ezio, like he had been listening to a story before he fell asleep.

Leonardo smiled – he begun to realise what had happened.

Fee had a tendency to fall asleep sitting up when he was exhausted; his head would start to slouch forward and his eyelids would droop, until he regained composure for a brief moment and started the cycle again. He must have started to do it last night on the stone, and Ezio brought him upstairs to save his friend any further hassle.

"Tranquillo, Fee," he soothed as he gently picked the baby up; "All will be well once we have you in your crib."

The eyelids fluttered but did not open. A small hand reached out to pull at Leonardo's hair, and the artist was careful to extract it when he placed the child in his crib.

"Sleep well, little one."

Fiorentino stirred, and stilled again. There was a moment when the artist thought he might wake up. It was early morning, he noted, and in the early morning Fee had become somewhat of a bell tower, waking him when he was hungry, but it seemed his usually alert little companion was too tired to move. He had played most of the night with a man unfamiliar to him. It would wear even the most hyperactive boys out.

A sudden, sharp blade appeared at Leonardo's throat, grazing the thin skin that shielded his jugular as a hand came to rest on his stomach and restrain him. For the artist's part, he stood very, very still.

"Is this how you greet friends?" his tone was light, but there was a hint of fear there.

"Leonardo! I apologise," Ezio said, sheathing his hidden blade with but a flick of the wrist; "I saw someone standing over Fee's crib and my reflexes responded before my brain could."

The artist waved him off with a smile on his face; "It's quite alright, Ezio. Come; let's leave him to his dreams."

They left the room, and behind them they could hear a faint gurgle, but no cry. Just for good measure they waited until they were in the workshop to speak again, which was when Leonardo told his friend of the dummies being set up in the yard, and when he mentioned his progress with the Codex page was slower than he thought.

"I may not be able to get it finished for a while."

"Take all the time you need, Leonardo."

"In any case, I doubt it will take much longer than today, if that. Thank you for taking care of Fee for me. I would never have come as far as I have if it weren't for that," the artist smiled up at him as he took his place again, prepared for another study session. He had no doubt Vincenzo would alert him should the baby wake up.

Ezio gave his own smile; "He is a lively boy, my friend. You have a fine son."

"Son?" he chuckled, "I'm not his father, Ezio. Merely his friend."

"A friend who does so much for him." His voice was sceptical.

"Perhaps I am a better friend than most, but a friend all the same."

"Leonardo, do you not want for children?"

"I…it's something I haven't given much thought to."

"Then forgive me for thinking you as Fiorentino's father, but that's what you are."

Leonardo, despite his unease, smiled as he looked at his work. "There are worse children to become fathers to."

"Maestro?"

They turned to see Vincenzo standing in the doorway, a look of hesitation on his face.

"Forgive me for interrupting, but the dummies are ready."

Ezio moved forward. As he went, he clapped a hand on his friend's shoulder, his smile broad and genuine.

"I will be back in a few hours, my friend. Try not to get lost in the page."