Athelstan showed him. At first, his mind dulled with sleep and wine, Cranston stared blankly but the significance of the friar’s discovery gradually dawned on him. Without more ado, the coroner began to finger the carving of the figure of Death, probing and pressing it.

‘There must be a secret compartment. I have heard of such in the Italian mode, built into chairs, tables and desks. I have even heard of hiding places in beds but never seen one.’

Their search was fruitless so they moved to the other bed post. They pushed different parts of the carving but nothing moved. Suddenly Cranston looked up and nudged Athelstan.

‘Look, Brother!’

Athelstan stared across at the bed post where a small block of wood on which the carving had rested had now opened outwards like a door.

‘The mechanism must be in this bed post, with a spring that runs here under the boarding and up into the other.’

Again they pressed, watching the small door close when Athelstan pushed the apple between the serpent and Eve. He pushed and it re-opened. Slowly they approached the cavity, each trying to control his excitement. Athelstan put his hand gingerly into the small, dark space and brought out two rolls of parchment. He ignored Cranston’s excited pleas to hurry and went over to the window, unrolling them carefully. The first was a love poem written in a rough hand in Norman French. At first Athelstan thought it was addressed to a woman but realised it was written to a young man. He handed it over to Cranston.

‘Make of that what you wish!’

The second was a small indenture or agreement. The top was perforated, so someone else must have a copy. Athelstan read and knew why John of Gaunt, Duke of Lancaster, was so indebted to Sir Thomas Springall, and why the merchant had possessed secrets which could have brought him even greater wealth. Cranston had already dismissed the poem, but when he read the indenture he sat at the foot of the bed stupefied, the parchment held loosely between his fingers.

‘This was written fourteen months ago,’ he said quietly. ‘As the Black Prince, father of the present king, lay dying. If the Lord Edward had known this, he would have had John of Gaunt’s head on a pole on London Bridge. If it was revealed now there would be a public outcry.’

‘So we know the reasons for Springall’s death,’ Athelstan said, ‘but not the hows, the wherefores, and above all the culprit or culprits. Look, Sir John, let’s follow the method of the Schools at Oxford. You sit on the bed, I’ll sit beside you. You will recite everything you know about each of the four murders, beginning with Sir Thomas Springall’s. Though in fact there was another killing, making five in all.’ He pointed to the parchment poem. ‘The young boy who died here must also be regarded as a victim.’