Mary Herbert, Countess of Pembroke (née Sidney, 27 October 1561 – 25 September 1621) was among the first Englishwomen to gain notice for her poetry and her literary patronage.

By the age of 39, she was listed with her brother Philip Sidney and with Edmund Spenser and William Shakespeare among the notable authors of the day in John Bodenham's verse miscellany Belvidere.

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.

After the death of Sidney's youngest sister, Ambrosia, in 1575, the Queen requested that Mary return to court to join the royal entourage.

After her marriage, Mary became responsible with her husband for the management of a number of estates which he owned including Ramsbury, Ivychurch,[5] Wilton House, and Baynard's Castle in London, where it is known that they entertained Queen Elizabeth to dinner.

[10] She died of smallpox on 25 September 1621, aged 59, at her townhouse in Aldersgate Street in London, shortly after King James I had visited her at the newly completed Houghton House in Bedfordshire.

She finished his translation, composing Psalms 44 through to 150 in a dazzling array of verse forms, using the 1560 Geneva Bible and commentaries by John Calvin and Theodore Beza.

This work is usually referred to as The Sidney Psalms or The Sidney-Pembroke Psalter and regarded as a major influence on the development of English religious lyric poetry in the late 16th and early 17th centuries.

[13] The importance of these is evident in the devotional lyrics of Barnabe Barnes, Nicholas Breton, Henry Constable, Francis Davison, Giles Fletcher, and Abraham Fraunce.

Their influence on the later religious poetry of Donne, George Herbert, Henry Vaughan, and John Milton has been critically recognized since Louis Martz placed it at the start of a developing tradition of 17th-century devotional lyricism.

Her original poems include the pastoral "A Dialogue betweene Two Shepheards, Thenot and Piers, in praise of Astrea,"[21] and two dedicatory addresses, one to Elizabeth I and one to her own brother Philip, contained in the Tixall manuscript copy of her verse psalter.

[23] June and Paul Schlueter published an article in The Times Literary Supplement of 23 July 2010 describing a manuscript of newly discovered works by Mary Sidney Herbert.