Complex sentence: In 1462, Margaret de Botreaux, 4th Baroness Botreaux, the 3rd Baron's daughter inherited the title and, because she outlived both her son and grandson, it then passed on her death to her great-granddaughter, Mary Hungerford, as 5th Baroness Botreaux.
Split into simpler sentences: In 1462, Margaret de Botreaux, 4th Baroness Botreaux, the 3rd Baron's daughter, inherited the title. She outlived both her son and grandson, so the title passed on her death to her great-granddaughter Mary Hungerford, as 5th Baroness Botreaux.