Mahaut or Matilda II of Boulogne was Countess of Boulogne in her own right and Queen of Portugal by marriage to King Afonso III from 1248 until their divorce in 1253.
Background
She was the daughter of Ida, Countess of Boulogne and her husband and co-ruler Renaud, Count of Dammartin. She succeeded her mother as Countess of Boulogne in 1216. She was the great-granddaughter of Stephen of England.
In 1223, Matilda married her first husband, Philippe Hurepel, Count of Clermont-en-Beauvais, a younger, arguably illegitimate son of King Philip II of France.
Career
Matilda"s then apparent barrenness was the true reason for their divorce. Her son reportedly renounced his rights and went to England, for unknown reasons. Apparently he survived his mother the Countess, but presumably did not leave issue.
Matilda"s daughter, having married a lord de Châtillon-Montjay, predeceased her, and presumably left no surviving issue.
The then-widow Adelaide"s husband had been William X, Count of Auvergne. Their son Robert of Auvergne succeeded also his mother in Boulogne and already in her lifetime acted as co-ruler.
Their heirs continued to rule Auvergne and Boulogne together. The ultimate heiress was Catherine de" Medici, Queen of France, but a couple of decades before her, the then Count of Auvergne, her great-grandfather, had sold Boulogne to the French throne, keeping just Auvergne.