Susan Bertie, Countess of Kent

Susan Bertie (born 1554) was the daughter of Catherine Brandon, Duchess of Suffolk, née Willoughby, by her second husband, Richard Bertie. Susan was the noblewoman memorialized by Lanyer at the beginning of the Salve Deus Rex Judaeorum (1611) as the "daughter of the Duchess of Suffolk." At sixteen years of age, she married Reginald Grey of Wrest, who was later restored as the fifth Earl of Kent. Widowed at age nineteen, Susan, now Dowager Countess of Kent, remarried to Sir John Wingfield in 1581 at age twenty-seven.

Susan was the first child of her mother's second marriage. Born one year after Susan was a brother, Peregrine Bertie, who later succeeded his mother Catherine Willoughby, 12th Baroness Willoughby de Eresby as the 13th Baron Willoughby de Eresby.

The dowager duchess and her second husband, devout Protestants, went into exile on the Continent with Susan and her brother for the remainder of the Catholic Queen Mary's reign, only returning in 1559 to the countess's elaborate manor house of Grimsthorpe in Lincolnshire after the accession of Queen Elizabeth, Susan being five years of age. In 1570, at the age of sixteen, Susan married Reginald Grey of Wrest, and, of course, left Grimsthorpe. Known at time of his marriage as "Master Grey", Susan's husband was restored as Earl of Kent by 28 March 1572, and Susan became Countess of Kent. A year later, on 15 March 1573, the earl died.

Because the Earl and Countess of Kent had been childless, however, the heir to the earldom was the earl's thirty-three-year-old younger brother, styled until then Henry Lord Grey of Ruthin. Susan Bertie Grey, now nineteen and Dowager Countess of Kent, and presumably unable to continue living in the new Earl of Kent's inherited residence, may at this time have been invited to live at Court. If so, the invitation was presumably issued at the behest of Queen Elizabeth I, who often kept a benevolent watch over younger ladies of the peerage in Susan's situation – certainly the queen would take an angry interest in Susan's remarriage in 1581.

Her second husband, Sir John Wingfield, was a nephew of Bess of Hardwick. They had two sons, Peregrine Wingfield, born in Holland, presumably named after her brother, and Robert Wingfield.

Aemilia Lanyer calls Susan Bertie "the Mistris of my youth, / The noble guide of my ungovern'd dayes." The poet was educated under the direction of the dowager Countess of Kent, whose Protestant humanist circle had a profound influence on the young Lanyer. The practice of being sent from one's family to be trained up in service in an aristocratic household, like that of Susan's, was then widespread.