Lady Harriet Pitt (née Villiers; 1680 â 21 October 1736) was an Anglo-Irish noblewoman who was the mother and grandmother of two British prime ministers, William Pitt the elder and William Pitt the younger.
Villiers was born into Anglo-Irish nobility as the daughter of Edward FitzGerald-Villiers and the Irish heiress Katherine FitzGerald.
In 1704, she married Robert Pitt, who was elected to the House of Commons in the 1705 general election. Together Harriet and Robert had four children:
Villiers died in 1736 and was buried at Layston Church in Buntingford, Hertfordshire. Her mother and her son are buried at Westminster Abbey.