What is the birthdate of this King of England, son of Edward, the Black Prince, whose court companion was Robert de Vere, Duke of Ireland?
Robert de Vere, Duke of Ireland: Robert de Vere, Duke of Ireland, Marquess of Dublin, and 9th Earl of Oxford KG (16 January 1362 – 22 November 1392) was a favourite and court companion of King Richard II of England. Richard II of England:  Richard, a son of Edward, the Black Prince, was born in Bordeaux during the reign of his grandfather, Edward III.
i don't know