The streets of York run deep with blood. Since Roman times, the city has played host to barbaric acts that some say have left indelible - if unseen -stains on the town's psychic fabric. And few were more barbaric than the immolation of the city's Jewry in 1190.
Clifford's Tower today is a well-preserved, picturesque stone keep dating to the late 13th century. But in 1190 it was still a wooden palisade, built by the Normans as part of their deployment of power following the invasion of 1066.
It was a harsh, unforgiving age - rife with torture, suspicion and feudalism. It was those factors that came together with one of Europe's periodic fits of anti-Semitic sentiment to create one of England's most infamous episodes.
Following the emotionally charged environment propagated by the crusades, there were many violent episodes throughout the country, fuelled by ancient religious hatreds. Following an incident in the city, the city's Jews felt compelled to seek refuge from a mob in the tower. So afraid were they that they barricaded the door against the castle's constable. The authorities, forced to act, attempted to regain the castle but the attempt descended into a even more violent mob attack.
So afraid were the Jews that many decided to commit self-immolation and set fire to large parts of the keep and thus died a horrible, self-inflicted death atop the hill. For the survivors, their fate was little better. Emerging from the smoking ruins, they were massacred by those who had lain siege to the tower.
Recriminations against the city were brought by the King's Lord Chancellor. The city's constable was dismissed and fines imposed on the townsfolk, but those responsible were never brought to justice.
Today, the keep sits atop its flowered hill and is inevitably said to be haunted by the tortured shades of those poor lost souls. A woman attempting to enter the keep was said to have been kept at bay by the clasp of ghostly hands around her neck. Red streaks that adorn the walls are likewise said to be the stains of blood.
Such claims can be treated with a degree of scepticism. The present keep is not, of course, the original building - which was consumed by the fire - and dates to the late 13th century. But it is undeniable that there is still an atmosphere amid its quietly crumbling stone and who can say to the motivations of the dead?