Mary Dudley, Lady Sidney

Mary Dudley
Mary Sidney by Hans Eworth, c. 1550–1555
Born	c. 1530–1535
Died	9 August 1586 London
Resting place	Penshurst Place, Kent
Known for	Lady-in-waiting to Elizabeth I
Spouse(s)	Sir Henry Sidney
Children	Sir Philip Sidney Mary Margaret Sidney (died as a child) Elizabeth Sidney (died as a child) Mary Herbert, Countess of Pembroke Robert Sidney, 1st Earl of Leicester Ambrosia Sidney (died as a child) Sir Thomas Sidney
Parent(s)	John Dudley, 1st Duke of Northumberland, and Jane Guildford

Mary Sidney (née Dudley) (c. 1530–1535 – 9 August 1586) was a lady-in-waiting at the court of Elizabeth I, and the mother of Sir Philip Sidney and Mary Sidney Herbert, Countess of Pembroke. A daughter of John Dudley, Duke of Northumberland, she was marginally implicated in her father's attempt to place Lady Jane Grey on the English throne and affected by his attainder.

Mary Dudley was one of Queen Elizabeth's most intimate confidantes during the early years of her reign. Her duties included nursing the Queen through smallpox in 1563 and acting as her mouthpiece towards diplomats. A sister of Elizabeth's favourite, Robert Dudley, Earl of Leicester, she remained always loyal to her family. She was the mother of seven children and accompanied her husband, Sir Henry Sidney, to Ireland and the Welsh Marches. From the 1570s the couple complained repeatedly about their, as they saw it, niggardly treatment at the Queen's hands. Still one of Elizabeth's favourite ladies, Mary Dudley retired from court life in 1579, suffering from ill health during her last years.

Mary Dudley was the eldest daughter among the 13 children of John Dudley, 1st Duke of Northumberland and his wife Jane Guildford. Mary Dudley was well-educated. Fluent in Italian, French, and Latin, she was interested in alchemy, romances, and writing poetry. Her copy of Edward Hall's Chronicles bears her annotations in French. She also became a friend, correspondent and frequent visitor of the scientist and magus John Dee.