Tag this record Other Last Name Mortimer Born / Died Birth Date: 0-00-00Death Date: 1382-01-05 Parents Mother: Grandison, Katherine de ( - 1349)Father: Montagu, William de (1301 - 1343/4) Marriages/Other Unions Mortimer, Roger de (1328 - 1359/60)Type: marriageUnion began: before 1352Union ended: exactly Siblings Female Montagu, Elizabeth de ( - 1359) Offspring From Mortimer, Roger de (1328 - 1359/60) Male offspring: Mortimer, Edmund de (1351/2 - 1381) Titles Details of Offices Bibliographic Sources View a list of abbreviations. The Complete Peerage of England, Scotland, Ireland, Great Britain, and the United Kingdom. 1887–98 (8 vols); 1910–59 (13 vols). 6 vols. Gloucester: Alan Sutton, 1982 Oxford Dictionary of National Biography.