Pitt was the grandson of Thomas Pitt (1653–1726), the governor of Madras, known as "Diamond" Pitt for having discovered a diamond of extraordinary size and sold it to the Duke of Orléans for around £135,000.Brown pp. 15–16 This transaction, as well as other trading deals in India, established the Pitt family fortune. After returning home the Governor was able to raise his family to a position of wealth and political influence: in 1691 he purchased the property of Boconnoc in Cornwall, which gave him control of a seat in Parliament. He made further land purchases and became one of the dominant political figures in the West Country, controlling seats such as the rotten borough of Old Sarum.
