A hagiography in the 11th century says that she was educated at the Abbey at Chelles, suggesting that she was linked to the Merovingian royal line, probably through her mother, Domne Eafe. While there, a young nobleman asked for her hand in marriage, but she replied that she was there to learn, not be married. The abbess tried to persuade her by every possible means to be married, but Mildred refused. The frustrated abbess threw her into a hot oven, but after three hours Mildred was unscathed.
The abbess then beat her and tore out a hank of her hair. Mildred wrote to her mother, enclosing the hair that had been torn out, and her mother immediately sent ships to rescue her. Mildred escaped the abbess on her own and found passage back to England, leaving her footprint embedded in a stone at the place where she first disembarked from the ship. She then joined her mother at Minster-in-Thanet (which her mother had established). Mildred became abbess in 694.
She was popular on the continent: there are several shrines/mentions of her in the Pas-de-Calais area of northern France. She died in Minster-in-Thanet some time after 732 after a lingering illness and was buried at the Abbey's Church of St. Mary.
Mildred's remains were moved to a new abbey church of Saints Peter and Paul, built by her successor as abbess, Edburga, by 748. She was a very popular saint and her relics drew attention from worshippers and pilgrims.
When the Danes invaded England they captured Minster-in-Thanet in 1011. The abbey was abandoned and the church downgraded to a parish church. Mildred's relics were transferred to Canterbury and the Church of St. Augustine.
Her sisters (Milburga of Much Wenlock and Mildgyth) were also saints, but it was her mother who was really interesting. We'll look into her next time.