William Lemon (1696 – 1760) was a successful mine owner (Gwennap Mine) and smelting house owner, becoming so successful through business and marrying into wealth that he was able to purchase, as his country home, the Carclew House and Estate from the Bonython Family of the Lizard for £3000 (pictured but which burned down in 1934) in Mylor Bridge.

The gardens were divided into parkland and private gardens, which became renowned throughout the county. He also constructed a grand townhouse, Princes House in Princes Street in Truro, which has five storeys and four bays, and is entered via a sweeping staircase of steps.  Adjacent to the Mansion House, it is now offices.