Eight hundred and twenty-two years after some 150 Jews were massacred in York's Clifford Tower, the most comprehensive commemoration of the worst anti-Semitic attack in the British Isles will take place today (Friday) in England's ancient Capital of the North. The event will be the culmination of an academic project chronicling the York Massacre using advanced technology and dispel, the organizers hope, one of the most pervasive myths of Anglo Jewry, that of the Cherem of York – the prohibition of resettling the city following the mass-murder of its Jews.

Clifford's Tower, also known as York Castle, is the most distinct landmark dominating the city's skyline and has served for centuries as York's symbol. First built as a Norman fort in 1068, it has been rebuilt many times and served as a military keep, prison, law court and today serves as a museum, but the only mention of the most bloody episode in its nine and a half centuries of history is a plaque at the foot of the tower unveiled by the Chief Rabbi of Britain and the Lord Mayor of York in 1978.

The York Massacre was just one of a wave of anti-Jewish riots that began eight months earlier at the coronation banquet of King Richard I, when a group of Jews who arrived to pay their respects were forbidden entry. Despite being under the King's protection, the Jews who had prospered for over a century as money-lenders, became the target for attacks by local noblemen who were anxious to wipe out their large debts. Murderous attacks began in London and spread to other Jewish settlements throughout England.

Richard, who had initially humiliated the Jews at his coronation, was concerned that the attacks were a challenge to his own rule and had a number of the perpetrators executed, while issuing orders to protect the Jews. This, however, put him on a collision course with the church, which he was eager to appease, and in early 1190 the new king embarked on a crusade to the Holy Land while not taking measures to enforce his order. The riots reached the northern towns of Norwich, Lincoln and Stamford in March; homes of Jews in York were attacked, forcing the 150 Jews of the town to take refuge in the royal castle. But as there was no force defending the tower, and the local knights and clergy were leading the attack, the Jews preferred to kill themselves rather than accept forced baptism. Those who did not commit suicide were killed when the castle was set on fire.

The rioters next burned all the records of the Jews financial affairs, thereby absolving them of their debts which would have been payable to the King following the death of the Jews.

The King's representatives held an inquest and fined the city, but none of the murderers were ever brought to trial, many of them later joining Richard on his crusade.
No memory was left in the city of the killings, but archaeological digs have revealed burnt remnants of the original structure beneath the tower.

"When I first arrived in York in 2006," says Professor Helen Weinstein, "as a Jew I was shocked to find that there was almost no public reference to the massacre." Weinstein, who had arrived at the University of York as the founding director of its Institute for the Public Understanding of the Past (IPUP) had of course heard of the massacre - her grandmother had even warned her that there was a Cherem, a rabbinical prohibition from living in York, and she took it upon herself to assemble a modern narrative.

Weinstein studied originally at Cambridge as an early modernist, specializing in the tabloid media and pornography of the late 1600s and 1700s, but her main interest was "who was reading these things? What kind of influence did they have on their lives?" Today, she regards herself as "a public historian," not focusing on a specific period in history, but instead working to share academic knowledge with the wider public through museums, heritage centers and media projects. "I don't think there is much importance to studying history if it doesn't have a relevance to today" she says. "Historians like to say their research isn't political and that the documents can talk for themselves, but I don't think that is true anymore. The public today consumes history as a whole. People are foraging everywhere, on the web, on YouTube, not just through visits to a museum, even through TV programs like Downton Abbey. Academics can be snobby and not look at these different genres, but we are no longer the curatorial voice and we have a wider duty than writing academic papers that only five people will read."

While there was a good deal of academic research and archaeological material relating to the York Massacre, Weinstein says that "the big challenge of the project getting all this out of the ivory tower and making it available to the public." As part of the project, she trained her students not only to write scholarly papers but also to produce much shorter texts that could be used on a website or in a podcast.

"Sometimes you have to summarize a whole MA thesis in a 30-word label." During the work, the idea arose to create an historical app that visitors to York could download to their smartphones and use to walk around the town on what has now become The York Jewish History Trail.

This is one of the first app of its kind, used for accompanying a journey through history, and it is to be used today for the first time as Professor Weinstein walks with a group through York, to Clifford's Tower. The Jewish History Trail, will also allow the city to finally put to rest the myth of the Cherem, which according to Weinstein, has no basis in any rabbinical document from medieval periods (unlike the famous Cherem placed on Spain following the expulsion of the Jews in 1492).

On the contrary - there is now ample evidence that Jews continued to live in York after the massacre, building houses and extending the local Jewish history, right up until King Edward I expelled the Jews in 1290. Jews returned there again at the end of the 19th century, though in small numbers, and York never became a major industrial center such as Manchester and Leeds, where much larger Jewish communities were established.

Despite the lack of a historical or halakhic basis, Professor Weinstein is not surprised that the myth of the Cherem has lasted so long. It is partly due to the difficulty of the local residents and authorities to confront York's past. "I think the city does feel ashamed for what has happened, despite it being so long ago," she says. "That is why I think the trail has been welcomed by many for offering a context in which to embrace York's Jewish past." But it was also the Jews who were not overly eager to reopen this chapter.

Jews were formally allowed to return to Britain in 1655, but the large waves of emigration from Eastern Europe only began towards the end of the 19th century, following the pogroms in Russia. With relatively little anti-Semitic persecution, Britain was seen as a safe-haven throughout the first half of the 20th century and especially during the Holocaust. "It would have been hard for the World War Two generation to grapple with the past in this way and see Britain also as a place where Jews were massacred," says Weinstein, "as they were not only in York but also in London, Lincoln and Norwich. Less than two years ago, seventeen skeletons found down a well in Norwich were identified as being of Jews murdered during that period. But from the responses I have been getting, there is now a new, self-confident Jewish generation that can look clearly at the past."