Margaret Paleologa
Margaret Palaeologa , was an Italian ruler Marchioness of Montferrat in her own right. She also married into the Gonzaga family, rulers of Mantua, making her Duchess of Mantua by her marriage to Federico II, Duke of Mantua. Margaret was the regent of Mantua as the guardian of her two sons from 1540 until 1556 in companionship with her brotherinlaw.
Margaret was born in Casale to William IX of Montferrat and his wife Anne of Alenon. Her mother was the third child of Ren, Duke of Alenon and his second wife Margaret of Lorraine, daughter of Frederick, Count of Vaudmont and Yolande of ValoisAnjou. Margarets maternal grandfather died two days after the birth of Anne.
Source: Wikipedia