As Ireland Descended into war in 1689, Londonderry was isolated and besieged. Unable to stop the advancing Irish army or to control the 'ungovernable rabble' that flooded into the city, the governor deserted. The city's defence was left to a few junior officers and thousands of armed civilians from across the northern counties. Within the walls, hunger, religious divisions and mistrust of the hastily elected leaders sparked rioting by men described by their commander as 'rogues' and 'sons of whores'. In the desperate fighting that followed, every assault on the city's defences ended in failure, as did every attempt to drive the Irish off Exasperated by inexperienced Irish officers, the Trench took over the siege. Determined to 'exterminate this race', General Conrad de Rosen had the city hemmed in by trenches and bombarded day and night by mortars and cannons. Protestants from the surrounding counties were rounded up and driven to the walls, behind which were crowded twenty thousand people, miserable, wet, starving and verminous. The city was saved by its sturdy defences and an outbreak of typhus that killed half the population (and all the children), a tragedy without which starvation would have forced an early surrender.

Meanwhile, the relief ships sat on the lough, afraid they would be unable to get up the river as it was blocked by a boom - which, after over three months of siege, shattered 'like glass' when rammed by a provision ship. All histories of the siege are based on the early printed accounts, written while the war in Ireland was still raging. This new book casts a critical eye over these sources, and for the first time provides a thorough analysis of the wealth of material that has since come to light in collections outside Ireland, including not only eye-witness accounts from the French participants, but the writings of governors Robert Lundie and John Michelburne. Every aspect of the siege is held up to careful scrutiny and retold. The result is an account of the siege very different to any published to date.