Masterpiece
Leonardo da ser Piero backed away, slowly, from the angry merchant's wife. Lisa had quite a temper.
"You want how much? You forget my eyebrows, mess up the horizon line, proportions, paint me all blurry and can't even do a smile properly, and you expect to be paid like it's a masterpiece! I can't believe this! Take your painting-" Leo managed to catch it as it was flung at his head "-and get out!"
Leonardo bowed and backed out, cursing inwardly. If this got out, he would be in serious trouble. He already had a reputation for being easily distracted and prone to abandon commissions, and his situation was not helped when the Battle of Arghien melted off the bloody wall. The Last Supper was already falling apart and some upstart sculptor from Florence was taking a lot of his commissions. If word got out that he'd messed up a simple portrait he was ruined.
"Lisa not happy?" the servant asked sympathetically, as he was being led back to his horse.
"uh...of course she was..." Leo interjected, improvising wildly. "It was my greatest achievement. I...uh...couldn't bear to be parted with it. It's...rich with symbolism."
"...right", the servant smirked.
Leonardo stood up straight. "An uneducated cretin such as yourself could not hope to understand my genius! Did you not hear your mistress pleading to possess such a masterpiece?"
The servant blinked, uncertain now. "I did hear...noise."
Leonardo, seeing he'd had an impact, pushed his luck.
"Would you not love to possess my masterpiece?"
"Are you selling?"
Leo almost agreed, before realising that he couldn't very well claim that he'd refused to sell his work to Lisa and then palm it off on her servant.
"Of course not! I'm keeping this forever! By God, I swear I shall never let it out of my sight!"
"You'll regret that oath" the servant told him, nodding sagely.
He was right.
He was absolutely right.
Centuries later...
"...Leonardo da Vinci claimed she was his finest accomplishment. He carried the painting with him whenever he travelled, and if asked why, would reply that he found it hard to part with. In actuality, the painting was a surprisingly ordinary sfumato portrait. Da Vinci's veneration for this work, many claimed, stemmed from something far deeper: a hidden message in the layers of paint..."