called a grand strategy to recapture Normandy and Anjou. The plan was that John would draw the French from Paris, while another army, under his nephew Otto IV, the Holy Roman Emperor, and his half-brother William attacked from the north. He also brought his niece Eleanor of Brittany, aiming to establish her as Duchess of Brittany. The plan failed when John's allies were defeated at the Battle of Bouvines. Otto retreated and was soon overthrown, William was captured by the French and John agreed to a five-year truce. From then on John also gave up the claim to Brittany of Eleanor and had her confined for life. John's defeat weakened his authority in England, and his barons forced him to agree to the Magna Carta in 1215, which limited royal power. Both sides failed to abide by the terms of the Magna Carta, leading to the First Barons' War, in which rebellious barons invited Prince Louis, the husband of Blanche, Henry II's granddaughter, to invade England. Louis did so but in October 1216, before the conflict was conclusively ended, John died. The official website of the British Monarchy presents John's death as the end of the Angevin dynasty and the beginning of the Plantagenet dynasty. Main line Baronial conflict and the establishment of Parliament All subsequent English monarchs were descendants of the Angevin line via John, who had five legitimate children with Isabella: Henry III – king of England for most of the 13th-century Richard – king of the Romans in the Holy Roman Empire Joan – queen consort of Alexander II of Scotland Isabella – wife of the Holy Roman Emperor, Frederick II Eleanor – wife of William Marshal's son (also named William), and later the English rebel Simon de Montfort. John also had illegitimate children with several mistresses. These children probably included nine sons called Richard, Oliver, Henry, Osbert Gifford, Geoffrey, John FitzJohn or Courcy, Odo or Eudes FitzRoy, Ivo, Henry, Richard the constable of Wallingford Castle and three daughters called Joan, Matilda the abbess of Barking and Isabella la Blanche. Joan was the best known of these, since she married Prince Llewelyn the Great of Wales. William Marshal, 1st Earl of Pembroke, was appointed regent for the nine-year-old King Henry on King John's death. Thereafter, support for Louis declined, and he renounced his claims in the Treaty of Lambeth after Marshal's victories at the battles of Lincoln