His maternal grandparents were Richard Mytton of Pontyscowryd and Garth , High Sheriff of Montgomeryshire and Dorothy Wynn .
He was the second son of Edward Devereux , 11th Viscount Hereford and his wife Catherine Mytton .
son 's maternal grandparents were Richard Mytton of Pontyscowryd and Garth , High Sheriff of Montgomeryshire and Dorothy Wynn .
He was the second son of Edward Devereux , 11th Viscount Hereford and his wife Catherine Mytton .