Mary Stewart, Countess of Buchan Scottish princess; fifth daughter and seventh child of James I of Scotland and Joan Beaufort (1401–1465) Parents Joan Beaufort James I of Scotland Children Siblings Annabella of Scotland Joan Stewart, Countess of Morton John Stewart, 1st Earl of Atholl James Stewart, 1st Earl of Buchan James II of Scotland Eleanor of Scotland Andrew Stewart Isabella of Scotland, Duchess of Brittany Alexander Stewart, Duke of Rothesay Margaret Stewart, Dauphine of France Partners Wolfert VI van Borselen