Doing my daughter-in-law's tree, I started with info from her father. He said that one of his great-uncles had been known locally as 'Jack of Hearts'. I pictured a him as quite an adonis with all the local lasses falling at his feet.
As the tree filled up I discovered that his father was called Hartley, so really he was 'Jack of Hart's', so as not to be confused with his cousin Jack, known as Jack o'Bella becasuse his mother was Isabella. Not nearly so glamorous
I love stuff like this, adding bits of family lore to names on the tree.