Edmund II (Ironside) is a curiosity among English Kings. He reigned for barely seven months, succeeding his father Ethelred II (Unraed) on St. George’s Day 1016 but dying “in suspicious circumstances” on St. Andrew’s Day the same year. He was the half-brother of Edward the Confessor and grandfather of Edgar the Atheling, thus the ancestor of every English monarch from 1154. As the grandfather of St. Margaret of Wessex, second wife of Malcolm III, he was the ancestor of every Scottish monarch from 1093 (except Donald Bain, Malcolm’s brother).
Edmund’s reign began from a bad position as the northern part of England was occupied by the Danes. Sveyn Forkbeard, their King, had temporarily supplanted Ethelred in 1013 but he died the following year and Ethelred’s authority was restored. Edmund, Ethelred’s third but eldest surviving son, fought alongside him and continued the struggle after his death, raising an army and defeating the Danes, under Sveyn’s son Cnut, at least twice near London until he suffered a reverse at Assandun in October 1016 and re-divided England with Cnut. He died the following month, possibly poisoned by Eadric Streona, his brother-in-law, and Cnut became King of all England. In any event, Cnut had Eadric executed at Christmas the following year.
Assessing Edmund as a King and commander is, therefore, even more difficult than with Richard III, his descendant. Another connection is that a play from c.1590, reputedly written by Shakespeare, is named Edmund Ironside, heavily featuring Cnut and Eadric. A sequel, Hardicanute, named for Cnut’s son and successor but one, is now lost.