Sibylla de Tregoz 1270 Ewyas, Herefordshire - 21 Oct 1334 Eaton, Herefordshire (1271–1334) Parents John de Tregoz, 1st Lord Tregoz Mabel FitzWarin Children Mabel de Grandson Catherine Montagu, Countess of Salisbury Peter de Grandison John Grandison Siblings Clarice de Tregoz Partners William de Grandison, 1st Baron Grandison