1228, London) Mathilde, married Rhys Gryg son of Rhys ap Gruffydd, ruler of the kingdom of Deheubarth. References Hertford, Richard de Clare, 3rd Earl of Hertford, Richard de Clare, 3rd Earl of Hertford, Richard de Clare, 3rd Earl of Richard 12th-century English people 13th-century English people Earls of Hertford Burials at Tonbridge Priory, Kent