The kettledrums in the galleys beat out the glamour of war, cymbals clashed, gongs sounded. The Genoese archers on the merchantman did their best but the galleys closed in and the yellow-robed, drug-emboldened Janissaries poured across the decks of the Saint Mark. Here and there, pilgrims and merchants fought and died in small groups. Individuals tried to escape into the darkness below; the Janissaries followed and the blood poured like water through the tar-edged planks of the ship. But the real struggle swirled around the mast where the knight stood, feet planted slightly apart. His great sword scythed the air until the gore swilled ankle-deep, causing further assailants to slip and slide as they tried to close for the kill. Beside the knight, the young boy, his face alive with the excitement of battle, screamed encouragement but no man could resist such a force forever. Soon the fighting died and the galleys drew off, their sterns packed with prisoners and plunder. The Saint Mark, fire licking at its timbers, drifted gently on a strengthening breeze until it became one blazing funeral pyre. When darkness fell, it had sunk. Here and there a body still bobbed on the surface, the only trace that Murder had passed that way.

December 1377

A murderously cold wind swept the snow across London with dagger-like gusts of ice and hail. At first it fell in a few white flakes, then thick and heavy, like God’s grace pouring from heaven to cover the wounds of that sombre city. The chroniclers in the monasteries on the outskirts of London tried to warm their cold fingers as they squatted in freezing carrels, writing that the terrible weather was God’s judgment on the city.

The snow continued to fall, God’s judgment or not, to carpet the stinking streets, and the mounds of shit in the lay stalls near the Thames where river pirates, hanging from the low scaffolds, turned hard and black as the river water froze. In savagely cold December, the heavy frost slipped into the city like an assassin to slay the beggars huddled in their rags. The lepers crouching in their filth outside Smithfield cried and moaned as the frost bit their open wounds. Aged, raddled whores were found frosty-faced, cold and dead on the corner of Cock Lane. The streets were empty, even the rats could not forage; the huge piles of refuse and the open sewers which ran down the middle of every street, usually full and wet with human slime, froze to rock-hard ice.

The blizzards hid the sky and made the nights as black as hell. No God-fearing soul went abroad, especially in Petty Wales and East Smithfield, the area around the Great Tower whose snow-capped turrets thrust defiantly up into the dark night sky. Guards on the ice-covered parapets of the fortress gave up their watch and crouched behind the walls. No sentry stood near the portcullis because the locks and chains had frozen iron hard, and who could open them?

Yet even on a balmy summer’s day the Tower would be avoided. Old hags whispered that the place was the devil’s work, and the black ravens, which swooped around its grim turrets, flocks of devils seeking human souls. The crones claimed human blood had been mixed in the mortar of its walls and that beneath its rocky foundations lay the skeletons of human sacrifices murdered by the great Caesar when he first built the fortress. Others, the few who could read, dismissed such stories as nonsense: the Tower and its great White Keep had been built by William the Conqueror to overawe London, and they scoffed at stories told to frighten the children.

Nevertheless the old hags were correct: the Tower had its macabre secrets. Beneath one of its walls ran cold, green-slimed passageways. Torches, old and blackening, hung listlessly from sconces rusting on the walls. No one had been down there for years, a mysterious warren of tunnels even the soldiers never frequented. Three dungeons were there but only two doors and in the central cell, a square black box of a room, sprawled a decaying skeleton. There was no witness to what it had been when the flesh hung plump on the bones and the blood ran like hot wine through heart and brain. The skeleton was yellowing now; a rat scurried through the rib cage and poked fruitlessly at the empty eye-sockets before scampering along the bony arm which rested against one wall, just beneath the crudely drawn figure of a three-master ship.

The assassin hiding in the shadows on the frozen parapet of the great Bell Tower knew nothing of such secret places, though he realized the Tower held great mysteries. He drew deeper into his cloak.

‘“The time has come”,’ he muttered to himself, quoting the Gospels, ‘“when all those things hidden in the dark shall be revealed in the light of day”.’ He squinted up at the sky. ‘Blood can only be avenged,’ he whispered, ‘by blood being spilt!’

Yes, he liked that thought; justice and death walking hand-in-hand. He gazed across at the dark mass of the Chapel of St Peter ad Vincula. Surely God would understand? Did he not brand Cain for slaying Abel, and why should murderers walk free? The assassin did not mind the biting wind, the steadily falling flakes of snow or the lonely, haunting call of the night birds down near the icy river.

‘There are things colder than the wind,’ he whispered as he turned inwards and meditated on his own bleak soul and the great open sore festering there. Soon it would be Yuletide and Childermass. A time of innocence and warmth, of food roasting slowly on turning spits. Green boughs would decorate rooms; there would be mummers, revelries, games, hot cakes and mulled wine. The assassin smiled. And, like every Christmas, the murderers would gather here in the Tower. He rocked himself gently to and fro. The trial would begin, the warnings were already prepared. He stretched his hands up against the night sky.

‘Let the blood flow,’ he murmured. ‘Let Murder be my weapon!’

The cross of St Peter ad Vincula caught his eye. ‘Let God be my judge,’ he whispered, thrusting his hands beneath his cloak, his eyes staring into the black night. He remembered the past and rocked himself gently, crooning a song only he understood. Now he felt warm. He would bathe his soul’s wounds in the blood of his victims.

Brother Athelstan stood on the tower of St Erconwald’s Church in Southwark and stared up at the sky. He chewed on his lip and quietly cursed. He’d thought the clouds would have broken up by now; they had for a while, and the stars had glittered down like jewels against a velvet cushion. Athelstan had wanted to study the constellations as the longest night of the year approached and see if the writer of the Equatorie of the Planets was correct. However, the wind had drawn the snow clouds like a thick veil across the sky.

The friar stamped his sandalled feet and blew on his freezing fingers. He picked up his ink horn, quill, astrolabe and roll of parchment, lifted the trap door and cautiously went down the steps. The church was freezing and dark. He took a tinder and lit the tapers in front of Our Lady’s statue, the sconce torches down the nave and the fat, white beeswax candles on the altar. Athelstan went back down the sanctuary steps and under the newly carved chancel screen, freshly painted by Huddle with a tableau depicting Christ leading souls from Limbo. Athelstan admired the painter’s vigorous brush strokes in green, red, blue and gold colours.

‘The young man has a genius,’ he muttered to himself, standing back to scrutinise the figures delineated there. He just wished Huddle had been a little more delicate in his depiction of a young lady with rounded juicy breasts whom Cecily the courtesan claimed was a fair representation of her.

‘Well, let’s see!’ Tab the tinker had shouted out before Ursula the pig woman jabbed a sharp elbow in his ribs.

Athelstan shook his head and went across to warm his hands over the small charcoal brazier which glowingly offered some heat against the freezing night air. He looked down the nave of the church, noticing the boughs of evergreens, the holly and ivy which Watkin the dung-collector’s wife had wound round the great broad pillars. Athelstan was pleased. The roof was mended, the windows glazed with horn. ‘More like a church now,’ he muttered, ‘than a long, dark tunnel with holes in the walls.’ Soon Advent would be over. The greenery had been placed there to welcome the newborn Christ. ‘Evergreen,’ the friar murmured. ‘For the evergreen Lord.’ A small shadow, deeper than the rest, slunk from the darkened aisle.