Ralph/Radulfus I de Limesi was the son of Hugo de Tosny, Lord Limesi, born 1015. His mother was Cristina de Conteville, born 1037.
Ralph was born 1040 and his wife, Cristina of Wessex, born 1044, daughter of Edward the Atheling (b.1016) and Agatha von Braunshwieg (b.1024.) At least, this is what I found.