Thomas West, 3rd Baron De La Warr (or 12th Baron) (1577-1618) was a politician and merchant who became governor of the colony of Virginia (c1609). He made his mark on the New World through the state, Native American people, bay and river of Delaware, which were all named after him. West married Cecily Shirley, the daughter of Sir Thomas Shirley, High Sheriff of Surrey and Sussex (1576) and MP for Sussex and later Steyning. The Shirley family seat was at Wiston House.

In 1649 Wiston House was purchased by Sir John Fagg, a prominent Parliamentarian soldier during the Civil War, MP for Steyning 1660-1701 and a non-conformist. He protected a small Quaker community (at least 4 people in 1676) and became friends with William Penn who lived only 4 miles away at Warminghurst. William was a regular guest at Wiston House, particularly during the Sidney election campaign in 1679 (see also Bramber).