Jolie made her way to the fifth arrondissement, crossed the Pont Saint-Michel, arrived in the Latin Quarter, walked quickly through the wide streets, crossed the peaceful university gardens, crossed the arcades between faculties and arrived with her tablet in her arms at the amphitheatre where she would receive her first class in Comparative History of Religions, in her penultimate term as an anthropology student.

She was a beautiful, fresh-faced girl, like any other of those waiting for the professor to arrive while they chatted and laughed in groups. Only those who came very close could tell her apart by the depth and seriousness of her gaze. She was alone, standing by the door to pass through the first students into the amphitheatre.

The seminar professor arrived with English punctuality. He placed his briefcase on the desk and from there gestured to the students, inviting them to enter.

Jolie liked the global perspective, so she climbed up the steps and placed her tablet on the table on the top step in the centre of the semi-circular classroom. From there she could see the teacher from the front and had a full view of the classroom.

"I am Marius Denis, we are 101 people in this seminar. Any comments on this before we start the class?" said the professor when silence fell.
A faint murmur filled the classroom. "We are a hundred" "round number" "what a coincidence" "nice number" "a magic number" "a snake that bites its tail" "capicua" "a pallidrome" "good omen" "no one can leave the course, it would break the spell!"

The teacher listened to the spontaneous and fragmented comments.
"Are we many or are we few?" Asked the teacher with a jovial smile that had an immediate sympathetic effect on his young students.
The answer came from the centre of the last tier.
"That's the perfect number for this seminar!"

The professor heard more than just the words. He heard the confident vocal modulation, the tone of her voice, dark and low, that seemed to come from a person older than the one he was observing.

A discreet but perceptible smile formed on his face as if the student's voice was giving more information to him than to the rest of the group.

"Will you tell us your name, please?"
"I'm Jolie, Jolíe Bonnet."
"Explain to us why you say that the number one hundred and one is the perfect number for this course, Jolie."

"Well, basically because, according to some beliefs, the number one contains the energy necessary for successful beginnings, mediated by the number zero which represents God. In this course we are promised to begin to study the origin and history of the beliefs."

"From that point of view, belief may be true, Jolie. What do the others say?"

The classroom was filled with opinions, with questions... The conversation became deeper and deeper, more and more interesting and complicated.

With a wave of her hand, Jolie switched on her tablet. The image of the blue planet unfolded on the screen and reflected in her eyes. In Jolie's pupils the terrestrial sphere moved as if it were a magic ball. At the touch of her finger, the different beliefs unfolded, all intertwining and expanding in the universe.

"According to what you say, all belief systems and all the procedures associated with them are a religion," said one student at the time. "Therefore witchcraft is a religion and therefore there are witches.

Jolie raised her chin, interested. Her eyes still reflected the terrestrial sphere. Everyone was looking at the teacher at that moment, but Professor Denis was looking at her.

At that moment, a blue butterfly flew across the room, zigzagged across the bleachers and landed on the ceiling, just above Jolie's head.

There was total silence in the classroom. It was a light silence, like the silence of the past, or the silence that is just before the future opens.

As Denis watched Jolie, fascinated, a myriad of blue butterflies filled the amphitheatre. She smiled. From her tablet, from the terrestrial sphere, the familiar figures, dressed in black with pointed hats, began to fly, on their brooms. They became entangled with the butterflies.

Jolie made a graceful, slow gesture. In unison, Marius rose from the podium, levitated to her. As he moved over the heads of his students, he understood that time had stopped for them and perhaps for the rest of the world.

When he was next to Jolie, he heard, inexplicably, in a distant way, the intemperate cackles of the witches that ordinary people consider so distasteful.

"We're having a big ritual today," said Jolie, "We're having a party. I've come to invite you.
Marius was an advanced researcher. What was happening to him was within the realm of possibility, but he never thought he would feel what he was feeling for a real witch.

"Will you take me to an island where there will be a big cake to make wishes?" Marius said, in a sentence that seemed very silly to himself.

We'll make a break in time, tomorrow we'll pick up the class where we interrupted it. Jolie said in reply.

It is rare for adults to gaze attentively at the firmament. That's why no one noticed the myriad of blue and black butterflies that crossed the Parisian sky looking for the sea and, in it, a mysterious island.

Only the children were witnesses to that day when, two decades ago, the great celebration that united the witches' caste with that of the sensitive men of the earth began.

Years later this memory would come back to them, abruptly, in a classroom.