In May 1264, Simon de Montfort defeated and captured King Henry III at the battle of Lewes. Montfort became ruler of England in all but name, and was able to pursue the baronial campaign for reform. The instability and unrest led to the persecution of Jews living in London. 1265, by permission of City of London, London Metropolitan Archives
Simplified transcript
In the week before Palm Sunday, the Jews of London were destroyed, and all their property was stolen. Many of them were stripped naked, and attacked, and afterwards murdered during the night. Five hundred of them were murdered. Those who survived were saved the justiciars and the mayor of London, having been sent to the Tower of London before the slaughter took place.