“The joy and euphoria caused by the end of the Schism at first put everything else in the shade, but the time came when the matter began to be investigated. And what had happened during those two months was clarified. What had caused—it was asked—a seasoned fighter like Cossa to be so suddenly weakened? What had frightened the belligerent Anti-Pope? What had he seen to turn him suddenly into a drooling and pitiful wreck of a man? Why had Frederick, Duke of Austria, hidden himself away in his castle in Innsbruck and wasn’t emerging from it? What had happened to the Anti-Pope’s companions who had fled from Constance with him? And what had happened to the Jew, Meir ben Haddar? Because the mage had vanished without trace. From that time, May 1415, no one ever saw Haddar again.”

“And all that,” asked Hejncze, feigning disbelief, “was understood to have been caused by Birkart Grellenort?”

“Correct,” said the Perfectus, nodding. “By Birkart Grellenort, Konrad’s acolyte and confidant, his ward and—as some go so far as to claim—his bastard. A magus. A theurge. A sortilegus. A necromancer. A metamorphiser who can change shape—”

“During the Council in Constance, Grellenort couldn’t have been more than—”

“Twenty years old,” said the Perfectus, finishing Hejncze’s sentence. “That’s right. A twenty-year-old had vanquished Meir ben Haddar, a mage said to be in league with Devil. So with whom… or with what could Grellenort have been in league?”

“Didn’t the Church do anything about this? Or the newly elected Pope?”

The Perfectus shook his head.

“During the Council,” he reminded Hejncze, “Johannes Hus was burned at the stake and a rebellion had flared up in Bohemia. Konrad of Oleśnica was made a bishop before the Council was over. A bishop who enthusiastically quelled revolts, who ordered heretics to be dragged through Wrocław town square by horses before being burned alive. The most loyal ally of the Pope and King Sigismund, an ally in troubling times. To carp at a man for such a trifling reason as employing a sorcerer? Oh, really. The affair was covered up, swept under the carpet. Expunged from the files. Treated as if it never happened. Formally, at least.”

“And informally?”

“A secret investigation was conducted. The results were kept secret, but we know what they were. At a certain moment we also took an interest in Grellenort.”

“After Grellenort began to use black magic to persecute Cathars and Beguines on the orders of the Bishop of Wrocław,” said Hejncze, deciding to speed up the conversation.