from Wemyss Fifeshire, Scotland

"15. SIR JOHN DE WEMYSS. This Knight having only one daughter, as may be seen in the tree of the family, resigned his lands, holding of the earl of Fife, to John de Wemyss of Rivas, his cousin, and heir-male, A.D. 1376, and was succeeded by him. He married ISABELLA ERSKINE, co-heiress of Sir Allan Erskine of Inchmartine, heir-female, also of Wemyss; and A.D. 1403 obtained from King Robert the Third a charter of confirmation of all the lands disponed to his grandfather by David. He left several children, and was succeeded by his eldest son.”
SOURCE: Farnie, Henry Brougham. (1860). The Fife Coast from Queensferry to Fifeness: Handy-Book of Fifeness@GoogleBooks: page 98.

Other Sources

• Balfour Paul, James. (1904), Vol. 8. Edinburgh: D. Douglas. @Archive.org: Vol. 8:480-483. Note: This source spells her name Isabella.
• Blackwood, W. (Ed.). (1889). Blackwood’s Edinburgh Magazine: “The Wemysses of Wemyss” (Vol. 145). William Blackwood & Sons. @GoogleBooks: May Issue, pages 691-92.
• Easson, D. E. (Ed.). (1947). Charters of the Abbey of Coupar Angus, Vol. I: Charters I to CXVII 1166-1376. In Publications of the Scottish Historical Society @Digital.NLS.UK: (Vol. 40, p. 206). University of Edinburgh for the Scottish History Society.
• Fraser, Sir William. (1888). Memorials of the Family of Wemyss of Wemyss, Vol. 1. @Google Books: pp. VII, XIX, XXI, XXIII, XXVIII, XXIX, 40-41, 44, 46, 51, 55, 58-60, 67, 78, 85, 409. Note: p. 83, fn. 1 refers to her as "Dame Isabel [Erskine]."
• Lewis, Frederick Lewis, William Ryland Beall (Ed.). (1999). The Magna Charta Sureties, 1215: The Barons Named in the Magna Charta, 1215....
• Old Dominion University Department of History (Ed.). (1986). Scotia: Interdisciplinary Journal of Scottish Studies (Vol. 10). Old Dominion University (Norfolk, Virginia). page 12.