In 1238, King Alexander II of Scotland needed to remarry after the death of his first childless spouse, Joan of England.
The marriage brought an alliance between the Scots and the Coucy lordship, and for the rest of the 13th century they exchanged soldiers and money.
[2] In her retinue was her chancellor Richard Vairement and her nephew Enguerrand de Guines, who came to have some influence in Scottish affairs.
On 9 June 1250 Marie and Alexander III were present in Dunfermline for the observance of the canonisation of Saint Margaret of Scotland and the transference of her remains to the new shrine.
In 1252 she attended the wedding in York Minster of her son Alexander III and Margaret of England with a great entourage of French and Scottish nobles.