John of Eltham, 1st Earl of Cornwall (15 August 1316 – 13 September 1336) was the second son of Edward II of England and Isabella of France. He was heir presumptive to the English throne until the birth of his nephew Edward, the Black Prince. Life John was born in 1316 at Eltham Palace, Kent. On 6 October 1328, at the age of twelve, he was created Earl of Cornwall. Caught in the throes of the war between his father, Edward II, and his mother, Isabella, his growing years were turbulent. He was passed between his parents and was even held in the Tower of London for a time before his brother, Edward III, led a coup against their mother and assumed his majority. Information on John is scant, but by most historical accounts he was highly competent, and highly trusted by Edward. He was named "Guardian of the Realm" when Edward III was out of the country, was asked to open Parliament in Edward's absence, and was named Warden of the northern Marches, which gave him virtual autonomy in that portion of England. As the younger brother of the English monarch, since early childhood marital negotiations were made for John: in March 1328 Edward III entered into negotiations for a marriage between his brother and María Díaz de Haro, heiress of the Lordship of Biscay. By contract signed on 28 September 1334, John was then betrothed with Maria de La Cerda, Lady of Lunel and daughter of Ferdinand de la Cerda (grandson of King Alfonso X of Castile) by his wife Juana Núñez de Lara, Lady of Lara. A dispensation was sought, but the contract was abandoned when relations between Edward III and King Philip VI of France worsened in late 1334. Marie married Charles d'Évreux at Poissy in April 1335. In December 1335 were made negotiations for a marriage with Joan, Countess of Penthièvre and heiress of the Duchy of Brittany; however, it doesn't seem that these arrangement resulted in an official betrothal. At sixteen he was a key commander in the Battle of Halidon Hill (1333), a devastating defeat for the Scots. Later he commanded an army in the southwest of Scotland that put down resistance to Edward Balliol, whose claims to the Scottish throne were supported by England. According to Scottish accounts, who view John as a ruthless destroyer, he burned down Lesmahagow Abbey when it