Events from the 1260s in England. Incumbents Monarch – Henry III Events 1260 Llywelyn ap Gruffudd attacks English forces in South Wales. 22 August – truce agreed between England and Wales. 1261 Early – following disputes, northern academics from the University of Cambridge attempt to set up a university at Northampton, suppressed by the Crown in 1265. 12 June – King Henry III of England obtains a papal bull releasing him from the Provisions of Oxford, setting the stage for a civil war over the power struggle between the crown and the aristocracy. July – Henry regains control of the government. 1262 Consecration of a priory church in Oxford, probably the largest of the Dominican Order in England. Canonisation of Richard of Chichester. 1263 January – Provisions of Westminster re-issued. April – Simon de Montfort, 6th Earl of Leicester, seizes control of southern England after Henry refuses to accept the Provisions of Oxford. 16 July – rebels occupy London. 2 October – Henry travels to Boulogne for an attempt to broker peace by King Louis IX of France; barons refuse to accept terms. Presumed date – Balliol College established in the University of Oxford by John I de Balliol on its modern-day site. 1264 23 January – King Louis IX of France issues the Mise of Amiens, a settlement between King Henry III of England and barons led by Simon de Montfort heavily favouring the former, which leads to the Second Barons' War. February – Second Barons' War begins as Henry returns to fight Simon de Montfort's rebels. April – targeting of Jews during the conflict with the Barons: Gilbert de Clare, 6th Earl of Hertford, leads a massacre of the Jews at Canterbury; at about the same time, another of de Montfort's followers, John fitz John, leads a massacre of Jews in London. 17–26 April – Second Barons' War: de Montfort besieges Rochester Castle in Kent but fails to take it. 14 May – Second Barons' War: the Battle of Lewes is fought between Simon de Montfort and King Henry III in Sussex. By the end of the battle, Montfort's forces capture both King Henry and his son, Prince Edward, and Henry is forced to sign the Mise of Lewes making Montfort the "uncrowned king of England". June – Simon de Montfort summons a parliament in London, the first to include Knights of the Shire. 17 June – A