The days passed, marked by the boring rhythm of meals and prayer. The nights passed. The latter were a torment, owing both to the biting cold and the inmates’ intolerable choral snoring. The days were more bearable. At least one could talk.

“Owing to anger and envy.” Circulos moved his goitre and blinked his suppurating eyes. “I’m in here owing to human anger and the envy of my good-for-nothing friends. They hated me because I achieved what they failed to achieve.”

“Namely?” asked Scharley with interest.

“Why would I explain it to you laymen?” said Circulos, wiping chalky fingers on his smock. “You wouldn’t understand anyway.”

“Try us.”

“Well, if you will…” Circulos cleared his throat, picked his nose and rubbed one heel against the other. “I achieved no mean thing. I determined the precise date of the end of the world.”

“Would it be the year one thousand four hundred and twenty?” Scharley asked after a short, polite silence. “In the month of February, on the Monday after Saint Scholastica’s Day? Not especially original, if I may say so.”

“You insult me.” Circulos stuck out the rest of his belly. “I’m not just some rabid millenarian or semi-literate mystic who parrots the chiliastic rubbish of fanatics. I researched the matter sine ira et studio, on the basis of academic sources and mathematic computations. Do you know the Book of Revelation?”

“Sketchily, but yes.”

“You recall that the lamb opened the seven seals, and John saw seven angels?”

“Absolutely.”

“And the number of the sealed was one hundred and forty-four thousand, and there were twenty-four elders, and two witnesses who were given the power of prophecy for one thousand two hundred and sixty days? When you add everything together and multiply the sum by eight—the number of letters in the word ‘Apollyon’—you get… Oh, there’s no point explaining it you, you wouldn’t understand anyway. Suffice to say that the end of the world will occur in July. On the sixth of July, to be precise, in octava Apostolorum Petri et Pauli. On Friday. At noon.”

“Of what year?”

“The present, sacred one: 1425.”

“Yeees.” Scharley rubbed his chin. “There is one snag, however…”

“Namely?”

“It’s September.”

“That’s no proof,” said Circulos. He shrugged, then looked away and ostentatiously buried himself in the straw.

“I knew it was no use talking to dunces,” he snapped. “Good day.”

Nicolaus Koppirnig, the mason from Frankenstein, wasn’t talkative, but his coldness and brusqueness didn’t discourage Scharley, who was fond of conversation.

“So you are an astronomer, then,” the penitent tried again. “And you were put in the clink. Which confirms that watching the sky too closely doesn’t pay for a good Catholic. But I’ll put two and two together and get a different answer, sir. The conjunction of astronomy and gaol can only mean one thing: you questioned Ptolemy’s theory. Am I right?”