The Countess was left rich under Leicester's will; yet the discharge of his overwhelming debts diminished her wealth. In 1604–1605 she successfully defended her widow's rights in court when her possessions and her good name were threatened by the Earl's illegitimate son, Robert Dudley, who claimed that he was his father's legitimate heir, thus implicitly declaring her marriage bigamous. Lettice Knollys was always close to her large family circle. Helpless at the political eclipse of her eldest son, the second Earl of Essex, she lost both him and her third husband to the executioner in 1601. From the 1590s she lived chiefly in the Staffordshire countryside, where, in reasonably good health until the end, she died at age 91 on Christmas Day 1634.