The daughter of Sir Adam Mure of Rowallan, she initially became the Steward's mistress. He married her in 1336, but the marriage was criticised as uncanonical, so he remarried her in 1349 following a Papal Dispensation dated at Avignon 22 November 1347.
They had at least ten children. Doubts about the validity of her marriage led to family disputes over her children's right to the crown. However on 27 March 1371, "The Lord John (who later took the title of King Robert III), Earl of Carrick and Steward of Scotland, first-born son of King Robert II" was declared heir to the Crown by Parliament in Scone Abbey.