Isidore was drunk. Sodden with drink in fact. After a week-long binge he was a complete wreck. His beautiful white drill suit was now a greyish yellow, filthy, torn, and covered in grease and stains; his breath and his entire body stank to high heaven of all the squalor and mess he had wallowed in for all that time.

He was washed, lectured and locked indoors for four days. He seemed ashamed and contrite. His purse containing the 500 francs had disappeared as had the savings book and even his silver watch, a precious heirloom bequeathed to him by his father the fruiterer.

On the fifth day he ventured out into the rue Dauphine. Curious looks followed him as he walked past the houses, head down, glancing furtively about him. He disappeared as he left town, making for the valley beyond. Two hours later he reappeared, giggling and bouncing from one wall to the other.

He never went back on the straight and narrow.

His mother kicked him out and he became a carter, driving coal trucks for Poigrisel and Co. – still in business today, as a matter of fact. His notoriety spread far and wide. As far away as Évreux people talked about Madame Husson’s Rose King and it’s become the local term for a drunkard.

All of which just goes to show – no charitable act ever goes entirely to waste.’

Dr Marambot rubbed his hands together as he came to the end of his story. I asked him if he had ever known the Rose King personally.

‘Indeed I did. I had the honour of closing his eyes for the last time.’

‘What did he die of?’

‘Delirium tremens, of course.’

We had reached the old fortress, a mass of ruins now dominated by two towers, one called Saint Thomas of Canterbury’s Tower and the other Prisoner’s Tower. Marambot told me how this prisoner had managed, using a nail and the position of the sun as it filtered through an arrow-slit, to cover the entire surface of the walls of his cell with carvings.