Mary Herbert, Countess of Pembroke (née Sidney; 27 October 1561 – 25 September 1621) was one of the first English women to achieve a major reputation for her poetry and literary patronage. By the age of 39, she was listed with her brother Philip Sidney, Edmund Spenser, and William Shakespeare, as one of the notable authors of her time in the verse miscellany by John Bodenham, Belvedere. The influence of her Antonius is widely recognized: it stimulated a revived interest in the soliloquy based on classical models, and was a likely source (among others) for both the 1594 closet drama Cleopatra by Samuel Daniel and Shakespeare’s Antony and Cleopatra (1607). Sidney was also known for her translation of Petrarch's "Triumph of Death", but it is her lyric translation of the Psalms that has secured her poetic reputation.
Mary Sidney was born on 27 October 1561 at Tickenhill Palace in the parish of Bewdley in Worcestershire. She was one of the four daughters of Sir Henry Sidney by his wife Mary Dudley, a daughter of John Dudley, 1st Duke of Northumberland. Her brother was the poet Philip Sidney (1554-1586).
As a child she spent much time at court, where her mother was a Gentlewoman of the Privy Chamber and a close confidante of Queen Elizabeth I. Like her brother, Philip Sidney, she received a humanist education which included classical languages, French, Italian, music and needlework. Following the death of Mary's youngest sister, Ambrosia, in 1575, the queen requested Mary to return to court to join the royal entourage.