Editing 1257 (section)

==== British Isles ====
* [[Battle of Cadfan]]: An English expeditionary army under [[Stephen Bauzan]] is ambushed and defeated by Welsh forces. The English are decimated by devastating guerilla attacks and the Welsh capture the English supply train. Stephen Bauzan is killed along with some 1,000–3,000 of his men. The remaining English flee the battle, Prince [[Llywelyn ap Gruffudd]] is said to have been present at the battle, collecting spoils from the fallen English army. According to sources, it is one of the greatest victories of a Welsh army in the field against a much more powerful English force.<ref>{{Cite web |title=Welsh Battlefields |access-date=2009-04-13 |url=http://www.welshbattlefields.org.uk/eng/?page_is=18 |archive-date=September 18, 2023|archive-url=https://web.archive.org/web/20230918044336/http://www.welshbattlefields.org.uk/eng/?page_is=18 |url-status=dead }}</ref>
* King [[Henry III of England]] relents to the demands of his son [[Edward I of England|The Lord Edward]] for assistance to fight the Welsh, originally made in [[1256]]). He joins him on a campaign to retake the territories lost to the Welsh forces led by Llywelyn ap Gruffudd.
* Henry III of England orders the production of a pure [[gold penny]] coin with a value of twenty pence. Unfortunately, the [[bullion]] value of the coins is about 20% higher than the nominal face value, leading to poor circulation, as coins are melted down by individuals for their gold content.
* [[Battle of Creadran Cille]]: Norman invading forces under [[Maurice FitzGerald, 2nd Lord of Offaly|Maurice FitzGerald]] are driven out by [[Gofraid O'Donnell]] in northern [[Connacht]] (Ireland). On [[May 20]], FitzGerald is killed in personal combat by O'Donnell.<ref>Chisholm, Hugh, ed. (1911). ''O'Donnell – Encyclopædia Britannica'', pp. 6–8. Vol 20 (11th ed.). Cambridge University Press.</ref>