Mary Stewart, Duchess of Richmond and Duchess of Lennox (1622–1685), formerly Lady Mary Villiers, was the daughter of the 1st Duke of Buckingham.
On 8 January 1634, at the age of 12, she married the 15-year-old Charles, Lord Herbert, eldest son of the 4th Earl of Pembroke and 1st Earl of Montgomery, but was widowed in 1635 when her young husband died of smallpox.
On 3 August 1637, she married the 4th Duke of Lennox, who was created Duke of Richmond in 1641.
They had two children:
After the death of her son, sometime before 1664, Mary married Colonel Thomas Howard (d. 1678) about whom little is known.
Maureen E. Mulvihill has built a case for Mary Villiers as the author of the poems published under the pseudonym Ephelia, including Female Poems...by Ephelia (1679).
Mary is the subject of several paintings by Anthony van Dyck.