The Duke of York was the first nobleman in the kingdom, in point of family and power. His claim to the throne of England was grounded on his descent from Lionel, third son of King Edward III. Lionel’s first wife was Elizabeth, daughter and heiress of William de Burgh, Earl of Ulster, in Ireland, in whose right, he (Lionel) was created Earl of Ulster; and because he had with her the honour of Clare, in the county of Suffolk, as parcel of the inheritance of her grandmother (Elizabeth, coheir of the last Gilbert de Clare, Earl of Gloucester and Hertford), he was in 1362, created Duke of Clarence, {23b} from which duchy the name of Clarencieux King of Arms, of the south parts of England, is derived. He had issue by Elizabeth his wife, one only daughter, Philippe, before mentioned, who married Edmund Mortimer, third Earl of March, grandfather of Anne Countess of Cambridge, who was the mother of Richard Duke of York, and grandmother of King Edward IV. and of King Richard III. The Duke of York enjoyed vast possessions in England and Ireland, in right not only of his paternal line of the houses of York and Cambridge, but also of his descent from the great and powerful families of Mortimer (Earls of March), Clare (Earls of Gloucester and of Hertford), and de Burgh (Earls of Ulster). He was closely allied to the great and noble family of Neville, from having married Cecily, daughter of Ralph Neville Earl of Westmoreland, besides being connected with several other noble and powerful families. {23a} Some historians mention the 23rd of May, as the day on which that battle was fought. {23b} From a place in Suffolk, called Clare, or Clarence.