Lady Mary Stewart (1720-1751) (1720–1751) Parents Alexander Stewart, 6th Earl of Galloway Lady Anne Keith Children Euphemia Mackenzie Frances Mackenzie Kenneth Mackenzie, 1st Earl of Seaforth Maria Mackenzie Siblings William Stewart John Stewart James Stewart George Stewart Keith Stewart Lady Charlotte Stewart Lady Catherine Stewart Susanna Leveson-Gower, Marchioness of Stafford Euphemia Stewart Lady Margaret Stewart Harriet Stewart John Stewart, 7th Earl of Galloway Alexander Stewart Partners Kenneth Mackenzie, Lord Fortrose