Adela de Warenne (born c. 1170) was an Anglo-Angevian noblewoman and the mistress of her half-first cousin King John.
[1] Her father was Hamelin de Warenne, Earl of Surrey, the illegitimate son of Geoffrey of Anjou, Count of Anjou, who was born when Geoffrey was estranged from his wife, Empress Matilda.
[2] He was the half-brother of King Henry II of England and was loyal to his brother.
He became jure uxoris Earl of Surrey on his marriage and adopted his wifes surname de Warenne.
[3][4] Her mother was Isabel de Warenne, 4th Countess of Surrey, the widow of William of Blois, Count of Boulogne,[5] the second son of Stephen, King of England and Matilda I, Countess of Boulogne.