|SOME NOTES ON MEDIEVAL ENGLISH GENEALOGY|
Volume 8, page 520:
He [Sir John Marmion (d. 1322)] m. Isabel.(j)
This appears from his foundation of the Winteringham chantry [in 1310] and it is possible that she was the daughter of Alexander Peck, but for this there is no sufficient evidence available.
Isabel was the widow of Ralph de Plaiz (d.1283). In an order for the assessment of dower in Easter Term 1301, Ralph de Plaiz is referred to as formerly the husband of Isabel, the wife of John Marmion [modern abstract, from the de Banco roll, British Library, Additional Manuscript 39,373, fo.181].
[The evidence that Isabel married both Ralph de Plaiz and Sir John Marmion was pointed out by Douglas Richardson in December 2001]