Elizabeth Poyntz (1587–1673), known as Lady Thurles, was the mother of the Irish statesman and Royalist commander James Butler, 1st Duke of Ormonde.

Thomas and Elizabeth had three sons:[7] —and four daughters:[b] When Black Tom died in November 1614,[26] Walter, her father-in-law, succeeded as the 11th earl, and her husband became heir apparent with the courtesy title of Viscount Thurles.

While the Ormond title was secure, the lands were claimed by Richard Preston, 1st Earl of Desmond, who had married Elizabeth, Black Tom's only surviving child in autumn 1614, shortly before her father's death.

As Walter refused to accept, the king arrested him and held him in London's Fleet Prison.

Lord Thurles drowned on 15 December 1619, when the ship that should have carried him to England was wrecked off the Skerries near Anglesey.

Her son James, aged 9, became the new heir apparent and therefore was styled Viscount Thurles.

In 1620 Lady Thurles married Captain George Mathew of Radyr and Llandaff in Glamorganshire, Wales.