Story in my family is that the Sackville christian name came from Lord Sackville who was an English General. My g.g.g. grandfather was William Sackville Turner born 1770 in Middlesex, his son was also William Sackville and a great uncle of mine was also called William Sackville. The Sackville name passed on to his 4 children and to their children.
Another g.uncle heard the story of the Sackville name from his father but unfortunately no one knows how, where, when the Sackville name came into the family.
The furtherest I been able to get back on the family is William Sackville Snr's father Barnard Francis Alexander Turner who married in London 1767 to Sarah Perry Tillett.