St Thomas Aquinas: Sustinare est difficillius quam aggredi. (To endure is more difficult than to attack.)

Reverend Mother Aquinas was buying buttered eggs in the English Market on the Friday morning when the city engineer was assassinated.

No one screamed. She remembered that afterwards. They just moved away.

The gas lamps in the gallery above the stalls had been extinguished, quite suddenly. Seconds later the shot rang out. Her heart thudded, just a single stroke, and her breath quickened as she was swept back by the moving bodies all around her. The thick darkness intensified the smell of blood, of raw meat, of wet clothes, stale sweat, dung and the pungency of damp sawdust, mixed in with the almost palpable odours of fear. There was an uncanny silence for a moment after the shot when, like a well-drilled platoon of soldiers, the crowd of people all stepped back from the centre of the market, back behind the stalls, crowding into the shadows, huddling against the walls on either side. The woman beside the Reverend Mother sucked in a great gulp of air and sobbed audibly. There was a rattle of rosary beads as though someone had started to pray and she herself sent up a quick appeal to God that she might be spared, not for her own sake, but for the work that she would leave unfinished. And, like everyone else, she held her breath waiting for the next shot.

Gun shots were an almost daily occurrence in Cork city – had been for years. Even now, even in the April of 1923, when the War of Independence was drawing to a close and Liam Lynch, chief of staff of the Republican Army, had been assassinated over a fortnight ago; yet in this rebel city the guns still rang out. At the sound of an explosion no Cork person hesitated. Even the youngest of the children instantly dived for cover.

A few more moments' hush, but no more shots exploded. Michael Skiddy lit a candle from his own stall and one by one the stallholders followed his example. The gas system at the market was notoriously unreliable and everyone was prepared with a candle by the till or money box. Michael Skiddy, the Reverend Mother suddenly remembered, had a candle lit even before the gas lamps went out. She remembered seeing on the tiled wall the shadow of a man who had been leaning over the stall talking earnestly in his ear. It had been a man in a belted raincoat with a slouch hat pulled well over his face. A member of the Republican Army, she had thought when she had seen him first – they were notorious for this unofficial uniform. She noticed that others avoided the stall, that they hesitated and then passed on. The Shadow of a Gunman, she said to herself remembering reading the review in the Irish Times of the Seán O'Casey play now showing in the Abbey Theatre in Dublin. We live our lives in the shadow of the gunmen, she was thinking now, as the superintendent of the market shouted, 'Patsy', handed the keys to the gallery to the woman and then, a few minutes later, one by one the gas lamps on the overhead gallery popped into life again.

But it had only needed one lamp to illuminate the body on the ground. Black coat, black trousers, top hat a yard away leaving the bald scalp with its fringe of grey hair exposed to view and the face hidden in the sawdust on the floor. No sign of an injury, but the people of Cork were used to dead bodies, used to the smell of death and this body looked undoubtedly dead. No one moved forward. It was best not to interfere with public assassinations.

In any case, the assassin was still there, still standing, still holding the gun in his hand. Only two minutes ago, James Doyle, the city engineer, surrounded by colleagues and market shoppers, had been halfway through a well-rehearsed speech about the wisdom of waiting to rebuild the whole market instead of just repairing the two stalls burned down over two years ago and the next minute he was lying dead on the ground and his audience had rapidly distanced themselves. All except for that one man. For a moment all that the Reverend Mother had seen, left exposed in the centre space, was the slumped figure of James Doyle, City Engineer, but then she recognized the other figure. Young Sam O'Mahony was standing a few yards from the body, standing very still and holding a small pistol in his hand. No one moved, but the Reverend Mother noticed that every head had turned to look at him. There was a long minute of silence, almost as though all were frozen and she wondered why he had not taken advantage of it in order to escape. Then Sam started violently, gave an inarticulate cry and flung the gun from him towards the stone fountain in the centre of the stalls. It hit the scalloped top basin, bounced against the beak of an elegantly carved long-legged heron, missed the second basin and fell with an audible splash into the murky waters of the curved stone bowl at the base. That seemed to break the spell; a low buzz of voices began. One or two people emerged from the shadows and went hesitantly towards the body. Mrs O'Mahony from behind her drisheen and tripe stall screamed, 'Sam!' and then stopped abruptly as though the sound was choked off.

In the frightened silence that followed, fifteen-year-old Lizzie Carlton dropped a box of onions. They rolled across the tiled floor and Lizzie hastily retrieved one from under the nose of the dead man. The two Murphy brothers, both butchers, came out from behind their stall, red-stained choppers and saws in hands, almost as though the chief engineer of Cork city was a mere carcass dragged in from the nearby lane and lying ready to be carved into neat joints.

The superintendent of the market shouted, 'Everyone stand still! Stay right where you are!'

The town planner, Robert Newenham, came forward, bent down and put a hand on the man's heart and Thomas Browne, the city engineer's assistant, followed him, looked back at the market superintendent and then said hesitantly, 'Shouldn't someone get the civic guards?'

At those words the two beadles, dressed in their official uniform, leaped forward and each grabbed one of Sam O'Mahony's arms. For a moment he looked stunned and then realisation dawned. His face was contorted as he struggled violently, shouting, 'I didn't do it! I didn't do it, I tell you. That gun landed on my foot. I just picked it up! I flung it away in case it would go off. I know nothing about guns! I've never touched a gun in my life.' He looked across the heads of the crowd over towards his mother's stall and yelled at the top of his voice, 'I didn't do it, ask my mother. She'll tell you that I've never owned a gun, never handled a gun. I don't believe in violence. I'm not a Republican or a Free Stater. I wouldn't do a thing like that.'

There was an inarticulate, choking sound from Mrs O'Mahony, and all heads turned towards her as she came forward, red, swollen hands extended in front of her, held out towards her son. Her mouth opened, but no words came, just a sound of dry retching followed by a great gush of blood that spurted from her nose and dripped down her chin, soaking the rough apron of pale brown sacking that covered her dress. She mopped her nose impatiently with the edge of her black shawl, but her eyes never left her son.

There had been times during the last fifty years when the Reverend Mother had wondered whether she had missed something from her life by not bearing children, but the anguished expression on Mrs O'Mahony's face made her feel that no joy could...