The Daily Mail put up the chart below that shows the common ancestral line of Kate Middleton (through her father) and Prince William (through his mother’s Spencer lineage). They share Sir Thomas Leighton and Elizabeth Knollys as great-great-great-great-great-great-great-great-great-great-great-great-grandparents, making them 12th cousins.
I posted the other day about another line of Catherine Middleton’s leading to Edward III in 1312. Until we start hearing some more details about the big day, there should be lots of space for more articles on Catherine Middleton’s family history. I just wish I could get 12 generations back as quickly!
Double-click for a larger view: