Philippa married her cousin, Edward III of England at York in 1327. She had estates in Tynedale and resided there when her husband was campaigning against the Scots. After 1337, Edward was occupied in military affairs in France, and it was Philippa who roused the English troops before their victory over the Scots at Neville's Cross, near Durham, in 1346. The Scottish king was captured in the fight.
After her return from Calais in 1347, Philippa sought permission from her husband for her bailiff, Alan de Strother, to work the mines at Alderneston, which had been productive under Henry III and Edward I. 'From this opening of the Tynedale mines by Philippa proceeded our coal trade, which, during the reign of her grandson, Henry IV, enriched the great merchant [Dick] Whittington and the city of London.' So says Agnes Strickland in her Lives of the Queens of England.