Dorothy Sidney, Countess Of Leicester

Dorothy Sidney, Countess of Leicester (née Lady Dorothy Percy), was born circa 1598 and died on 20 August 1659. She was the eldest daughter of Henry Percy, 9th Earl of Northumberland, and Lady Dorothy Devereux. Her family background included notable siblings, such as her sister Lucy Hay, Countess of Carlisle, who was known for alleged involvement in political intrigues, and her eldest surviving brother Algernon Percy, who became the 10th Earl of Northumberland.

In 1615, Dorothy Percy married Robert Sidney, who later became the Earl of Leicester. The marriage produced twelve children. Among their children were Dorothy (1617–1683), who married Henry Spencer, 1st Earl of Sunderland; Philip (1619–1697), who became the 3rd Earl of Leicester and married Lady Catherine Cecil; Henry, who was created Earl of Romney but died unmarried and without issue; Algernon, who also died unmarried and without issue; Robert, who died young; and Lucy (died 1685), who married Sir John Pelham, 3rd Baronet.

The available information primarily details her familial relationships, marriage, and offspring.