Catherine Michaela of Spain was Duchess of Savoy by marriage to Charles Emmanuel I, Duke of Savoy. She ruled the duchy several times as regent in Charles Emmanuel's absence, notably during his campaign in 1594. She was the younger surviving daughter of Philip II of Spain and Elisabeth of Valois.

Margaret of Savoy was the last Habsburg Vicereine of Portugal from 1634 to 1640. In Portuguese she is known as Duquesa de Mântua, being by marriage the Duchess of Mantua and Montferrat. She was also regent of Montferrat during the minority of her daughter from 1612.