In truth he'd been sketching a still life in his cottage all that evening, but the sheriff declared that he had been seen stealing the saddle, so he was thrown in prison until he had served his time and paid back the debt. He had no family to back him, and no source of income in prison. Effectively he was locked away for life.
He had no money to buy candles from the prison warden, and his cell had no windows. He was in darkness all the time. Once a day (he hoped it was once a day; it is hard to tell when one is hungry and thirsty all the time), the flap at the bottom of his cell's door would slide open, and a guard would push a bowl of gruel forward through the dim shaft of light. The flap would be closed as soon as the bowl was within the cell, and he learned to run towards the light as soon as he heard the flap being slid back, because he had to compete with the rats for the gruel. He had to eat the gruel in about ten minutes and place the bowl against the door-flap for collection. If he failed to do so, there would be no bowl the following day.
He discovered within an hour of his incarceration that he was not really alone with the rats in the cell. The wall opposite his cot had iron manacles bolted to it, and the dessicated body of the cell's last human inhabitant still hung from them. He decided it was a blessing that the walls were too smooth for even the rats to climb up, and the corpse was too dry to stink. Much.
He decided to name the dead prisoner Richard.
When he wasn't busy collecting gruel-bowls or trying to avoid bumping into Richard as he paced his cell, he would lay on his cot with the fleas and the lice and think of light.
He remembered sketching a poppy field in the vivid autumn gold of a late afternoon.
He remembered running with his box of artist's tools to the pasture, just before dawn, so he could draw the sheep grazing as the sun rose.
He remembered moving his chair until the highlights and shadows from the hearth-fire were just right. That was for the still life he was working on the night before he was arrested. He remembered he was especially proud of how he had captured the reflections on the pewter tankard.
In a dream he walked through the local apple-orchard at midday. He found a ripe apple, picked it, and bit into it. When he awoke, the after-taste in his mouth was that of gruel, and that was when he realised he had been locked away for a very long time.
He sat on the edge of his cot and concentrated on feeling where the other objects in the room were, rather than trying to see in the eternal dark. The wall opposite the cell door was easy; it was colder in that direction. The wall with the door in it was not only warmer, but had a different echo, because some of the stone wall was replaced by wooden door. The wall with Richard on it was different again. He practised, and eventually he could rise from his cot and know exactly where Richard was without touching him.
Richard gave a sudden lurch about half an hour after bowl-collection one day. He gingerly inspected his cell-mate and discovered that the flesh on his forearms had come away, causing Richard's arms to slide down in the manacles until the wider and still-intact collection of hand-bones caught him. He felt the rats under his feet and deduced from their movements that they were feeding on the fallen Richard-jerky.
"I hope you make them ill," he said aloud to his friend. It was the first time he had spoken aloud since he had been imprisoned, and his voice came out somewhere between a croak and a whisper.
After that he decided to tell Richard stories, both to help keep his voice and to pass the time. The poor man had been in prison longer than he had — surely even out-of-date news would amuse him.
The village gossip got re-told so many times even he got sick of it, so he began to tell Richard about drawing. He started by apologising for being a bore, but Richard said nothing about stopping, so that encouraged him.
"My old master explained it very well," he said. "People think it's about drawing what's in front of you, but that's not true. What you really want to aim for is to represent the light. I was known for my natural-light landscapes, but lately I'd been practising working with firelight. It's a bit harder, because it's not steady. It moves around. You see this lovely gleam or shadow, and you grab your chalks and start to represent it, and the fire dies down or someone puts another log on, and the light changes entirely again. It's the same thing with candles or lamps. My old master used to keep several candles handy and burn them down a finger-width at a time to keep things consistent."
Richard didn't comment, but he seemed to enjoy listening.
He was asleep on his cot when the running and shouting came close enough to hear. He started — it was strange to hear a voice that wasn't his own — but the voices came closer and he could make out what they were saying.
"Down with the tyrants! Free all the prisoners! Liberate our brothers!"
He rose from his cot and approached the door, wondering what on earth they were going on about.
"Don't worry," he told Richard. "I'll get it sorted."
Someone pounded on his door, and he started back, crying out. "Brace yourself, Richard," he said. "I think we're in for a brawl."
"Is anyone in there?" someone shouted on the other side of the door. "Can anyone hear me?"
"We mean no harm!" he called back. "Please, we are not your enemy!"
"There's some in this one!" he heard, and then cracking, creaking sounds, as if they were applying crowbars to the door.
He saw a vivid gold rectangle outline where the door was supposed to be, and realised they were breaking into his home. He thought of hiding under the cot, but it was too low to the ground for that.
With a crash the door gave way and fell to the floor. He sank to the ground, blinded by the lamps in the corridor and the glaring torches held by the men standing without.
"We're here to rescue you," one said, walking over the door, torch in hand.
But he covered his face with his hands and screamed.
"Put me back in the dark!"