'Why, sir, to take over the Tower. Its roofs will turn to gold, its walls to gleaming white ivory. The angels will set up camp there and prepare a worthy tabernacle for the return of Le Bon Seigneur Jesu.'

At this surprising announcement all Four Gospels leaned forward, their brows touching the earth.

'And who told you all this?' Athelstan asked as they sat back on their heels.

'I had a vision,' First Gospel replied. 'I was once a shoemaker in the town of Dover. I went up on the cliffs and I heard the voices. "Go," they said, "go to the banks of the Thames, set up camp and await our return." '

'And these three ladies?' Athelstan asked.

'They are my wives. They, too, are included in the Great Secret.'

'I wish I had visions like that,' Sir John muttered out of the corner of his mouth. 'Good ale, fresh meat and all three in bed at the same time.'

'Hush, Jack!' Athelstan warned him.

'We came here four years ago,' First Gospel went on sonorously. 'At first Widow Vestler turned us away but then she thought otherwise. We set up camp. This cottage was already standing.'

'And when will St Michael come?'

'Why sir, the year of Our Lord, thirteen eighty-one.'

'Why not thirteen eighty-two?' Athelstan asked.

'One, three, eight and one make thirteen!' came the sharp reply. 'If you count the figures together, they come to thirteen. Now one and three is four, and we are the Four Gospels preparing the way!'

Athelstan gaped in astonishment. Of all the theories he'd heard, both sublime and ridiculous, this was the most bizarre. Yet the Four Gospels seemed harmless enough, probably swinging between sanctity and madness. He smiled to himself. Prior Anselm always believed the line between the two was very thin.

Sir John pointed to the gap in the hedge. 'And you go out there on to the mud flats to watch and wait?'