In 1387 Robert de Vere 1st Duke Ireland (age 24) and Agnes Launcekrona Duchess Ireland were married. She by marriage Duchess Ireland, Marchioness Dublin, Countess of Oxford. He the son of Thomas de Vere 8th Earl of Oxford and Maud Ufford Countess of Oxford (age 42). He a great x 3 grandson of King Henry III of England.