Mary Fiennes, Baroness Dacre (1524–1576; née Mary Nevill) was the daughter of George Nevill, 5th Baron Bergavenny by his third wife, Mary Stafford, daughter of Edward Stafford, 3rd Duke of Buckingham. She married Thomas Fiennes, 9th Baron Dacre (c. 1515-1541), who was convicted of the murder of a gamekeeper and hanged as a common criminal at Tyburn in 1541. The family was stripped of its lands and titles by Henry VIII.
In the following years, Mary battled to have the properties restored on behalf of her children, and on her ascension in 1558 Elizabeth restored the title of Baron Dacre to Mary's second son Gregory, her eldest son Thomas having died of the plague at age 15.
By her first husband, Mary Fiennes was the mother of:
1) Thomas Fiennes (1538–1553)
2) Gregory Fiennes, 10th Baron Dacre (1539–1594)
3) Margaret Fiennes, 11th Baroness Dacre (1540–1611). Margaret married Sheriff Samson Lennard of Knole and their daughter Elizabeth married Sir Francis Barnham, this connecting Mary to the Barnham family.
Mary Nevill married twice after her first husband's death and had several other children about whom little is known. Mary Nevill is the sitter in two significant portraits by Hans Eworth.