Surrounded for months by a Jacobite army, thousands died of fever, dysentery and famine in the beleaguered city. As food supplies dwindled a cat came to be worth four shillings and sixpence; a mouse cost sixpence; and a dog's head sold for half-a-crown.
But the Protestant folk-memory is that their ancestors endured the worst that the Catholic besiegers could inflict, and emerged triumphant. This weekend's march is not only a celebration of that victory, but also a declaration of the deep-seated Unionist belief that, 300 years on, they remain under political siege.
The Apprentice Boys, who organise the march, take their name from the 13 apprentices who closed the city gates against the forces of James II, thus precipitating the siege. The grouping is smaller than the Orange Order and technically independent from it, but in practice the memberships of the two overlap. Their primary purposes - organising Protestant parades - are identical.
The August marches which commemorate the lifting of the siege are largely controlled by Apprentice Boys clubs. The most important of these are in the city itself, but branches exist all over Northern Ireland and, in a small way, in the Irish Republic, England, Scotland and Canada. The vast majority of the 120,000 members, led by a local newsagent and a community worker, are working-class Protestants who see themselves as making an important political statement.
Between the 1920s and 1970s Londonderry took on another political significance. Nationalists in the city complained that district boundaries were manipulated to ensure that the council remained in Unionist hands. The violence that ensued left scars on the city, but the 1990s saw a remarkable renaissance. But last month's return of large-scale riots have tarnished its new image, which will suffer even more if the weekend brings fresh violence.Reuse content