Euphemia was the elder daughter of Uilleam III, the last O'Beolan Mormaer of Ross.
King David II desired to bestow an earldom on Walter de Leslie, who had distinguished himself in combat in Europe and in Alexandria, Egypt.
[1][2] The charter of the earldom of Ross and of the lands of Skye was made to them in their own favor and that of their heirs male and female in reversion.
[3] She married Leslie, by papal dispensation, dated 24 November 1366 (variously reported as December 1367), the dispensation being necessary in that Walter Leslie had had illicit intercourse with a woman related within the fourth degree of kinship with Euphemia[4][5] Leslie predeceased her in 1382, whereupon she married, secondly, Alexander Stewart, 1st Earl of Buchan, better known in history as "The Wolf of Badenoch."
However, on 9 June 1392, Pope Clement VII issued a commission to dissolve this marriage and then on 5 and 15 December to grant a divorce.