[3] Ermengarde was born c. 1170 to a minor French noble, Richard I, Viscount of Beaumont-le-Vicomte,[4] Fresnay and Ste-Suzanne, and Lucie de l'Aigle [fr] (died aft.
[2][5] Ermengarde married King William I of Scotland at the royal chapel at Woodstock Palace,[6] near Oxford, in England on 5 September 1186, performed by Baldwin, Archbishop of Canterbury.
[7] The marriage was arranged under terms of the Treaty of Falaise by King Henry II of England, who was at the time the acknowledged overlord of Scotland.
William considered her status beneath him, but agreed after Henry offered to pay for the entire wedding, land valued at 100 merks and 40 knight's fees, and to return the castles that he had forfeited as her dowry, one of them being Edinburgh.
Due to the illness of William, Ermengarde took over some of his duties during his later years, and there is evidence that she wielded considerable influence in public affairs.