| Name | Relationship with Brian Mason | Civil | Canon |
|---|
| Gerard, William | Husband of the 13th cousin 15 times removed | | |
| Gerberge | 30th great-grandmother of the wife | | |
| Germans, Heinrich I The Fowler King Of The | 31st great-grandfather | XXXIII | 33 |
| Germany, Hadwige de Saxe Princess of | 30th great-grandmother | XXXII | 32 |
| Germany, Hedwiga of | 30th great-grandmother | XXXII | 32 |
| Germany, Heinrich I King of | 31st great-grandfather | XXXIII | 33 |
| Germany, Otto I King of | 30th great-granduncle | XXXIV | 33 |
| Gibson, Mary | 8th great-grandmother of the wife | | |
| Gibson, William | 10th great-grandfather of the wife | | |
| Gibson, William | 9th great-grandfather of the wife | | |
| Giselda | Wife of the 4th cousin 28 times removed | | |
| Golborne, John | 17th great-grandfather of the wife | | |
| Golborne, Margaret | 16th great-grandmother of the wife | | |
| Goodere, Anne | 11th great-grandmother | XIII | 13 |
| Gordge, Magdalyne | 13th great-grandmother of the wife | | |
| Goronwr, Madog Fychan ap | 19th great-grandfather of the wife | | |
| Goronwy, Goronwr Fychan ap | 20th great-grandfather of the wife | | |
| Goth, Avelina | 28th great-grandmother of the wife | | |
| Graye, ?? | 11th great-grandmother of the wife | | |
| Graye, Allis | 10th great-grandmother of the wife | | |
| GREAT, ALFRED THE, King of England | 32nd great-grandfather | XXXIV | 34 |
| Grey, 1 Baron of Ruthin Roger | 19th great-grandfather | XXI | 21 |
| Grey, Elizabeth | 15th great-grandmother of the wife | | |
| GREY, Elizabeth Eleanor | 16th great-grandmother | XVIII | 18 |
| Grey, Henry, Duke of Suffolk | Husband of the 4th cousin 13 times removed | | |
| Grey, Lady Jane | 5th cousin 12 times removed | XXIV | 18 |
| Griffith, Agnes | 15th great-grandaunt of the wife | | |
| Griffith, Ap Henry | 12th great-grandfather | XIV | 14 |
| Griffith, Catherine | Half 13th great-grandaunt of the wife | | |
| Griffith, Dorothy | Half 13th great-grandaunt of the wife | | |
| Griffith, Isabelle | 6th cousin 13 times removed | XXVII | 20 |
| GRIFFITH, Margaret Verch | 11th great-grandmother | XIII | 13 |
| Griffith, Sibyl | 6th cousin 13 times removed | XXVII | 20 |
| GuillameVIII, Deuc de Aquitaine | 26th great-grandfather | XXVIII | 28 |
| GuillaumeII, Talvs de Ponthieu, Ct de Ponthieu | 23rd great-grandfather | XXV | 25 |
| GuillaumeIII, Duke of France | 30th great-grandfather | XXXII | 32 |
| Guiscard, Bohemond I Prince of Antioch | Half 26th great-granduncle | XXX | 29 |
| Guiscard, Bohemond II Prince of Antioch | 1st cousin 26 times removed | XXX | 28 |
| Guise, Mary of | Wife of the 4th cousin 13 times removed | | |
| Guzman, Leonora de | Wife of the half 3rd cousin 19 times removed | | |
| Hainault, Bertha de (von Holland) | 26th great-grandmother | XXVIII | 28 |
| Hainault, Isabella of, Queen of France | Wife of the 23rd great-granduncle | | |
| Hainult, Holand -, Earl of Kent, Thomas de | Husband of the 3rd cousin 19 times removed | | |
| Hainult, Holand -, Earl of Kent,Edmund de | 4th cousin 18 times removed | XXVIII | 23 |
| Hainult, Margaret | 4th cousin 18 times removed | XXVIII | 23 |
| HANOVER, Augusta | 12th cousin 5 times removed | XXXI | 18 |
| HANOVER, Edward of | 13th cousin 4 times removed | XXXII | 18 |
| HANOVER, Frederick of, Prince of Wales | 11th cousin 6 times removed | XXX | 18 |
| HANOVER, GEORGE I OF | 9th cousin 8 times removed | XXVIII | 18 |
| HANOVER, GEORGE II OF | 10th cousin 7 times removed | XXIX | 18 |