| Louis de Brienne Vicompte of Beaumont |
Sir Alexander Comyn |
| Agnes |
Joan Latimer |
| Henry de Beaumont Lord Beaumont | Alice Comyn Countess of Buchan |
| b. ca 1280 d. 10 Mar 1340 . Yr s. 1st baron. Also earl of Buchan. Constable of England. |
b. d. bef 10 Aug 1349 . 1st dau, co-heir. Suo jure, Countess of Buchan (S). |
| > Isabel de Beaumont < Elizabeth Beaumont > John Beaumont Lord Beaumont < Joan Beaumont Catherine Beaumont Agnes de Beaumont |