sentences:  The Wheelwrights maintained the estate until Robert's death in 1965.With plans in motion to transform the rural scenic estate into housing developments, local citizens convinced the state that it should preserve the land.With a grant from the United States Land and Water Conservation Fund that had been established earlier that year, and with additional grants from Pierre S. du Pont's Longwood Foundation, the state purchased the and established Brandywine Creek State Park in 1965.