By her first husband she had no children, by her second a son who died in infancy, and a daughter, Jeanne d'Albret, who became the mother of Henry IV.
She had sworn to her first husband on his deathbed not to marry again, and had even imprisoned and exiled Romanus, who was suspected of aspiring to the throne.
He died soon afterwards, leaving his inheritance to his daughter Adela, whose first husband was Hugh the Great, the brother of king Philip I.
Cynthia explained this was a second marriage and her first husband had died.
From her first husband she took, during no small part of her life, the appellation Marguerite d'Alengon, and from her second, Henri d'Albret, king of Navarre, that of Marguerite de Navarre.
In 1584 the long-suffering earl of Shrewsbury was relieved of his fourteen years' charge through the involuntary good offices of his wife, whose daughter by her first husband had married a brother of Darnley; and their orphan child Arabella, born in England, of royal descent on the father's side, was now, in the hopeful view of her grandmother, a more plausible claimant than the king or queen of Scots to the inheritance of the English throne.
By her first husband she was the mother of Marcus Marcellus (q.v.), who died in 23 B.C. (2) Octavia, daughter of the emperor Claudius, was the wife of Nero, by whom she was put to death.