The media, particularly CNN, is going nuts over the Duke and Duchess of Cambridge's baby's ancestry, in particular, this bit about Catherine's being the first "commoner" to marry into the royal family since "the 17th century." I don't understand what the reporter, Ashley Fantz, means here. Technically, anyone who is not of royal rank or does not have a peerage is a commoner. Does she mean that the former Catherine Middleton is the first person without a title or relationship to nobility to marry into the royal family since whenever? Then, it seems to me that we need to look farther back than the seventeenth century. Does she mean that Catherine Middleton is the first person to marry into the family without a title of her own? Then Ms. Fantz is incorrect. Lady Diana Spencer was nobility, not royalty, as was Lady Elizabeth Boyes-Lyon, the mother of Queen Elizabeth II. I think with her seventeenth century reference Ms. Fantz means the daughter of the Earl of Clarendon, Anne Hyde, who was the first wife of James II, and was the mother of both Mary II and Queen Anne. But Anne Hyde is more comparable to Diana Spencer than Catherine Middleton; she was the daughter of an earl.
Let's look back a little more. Before Henry VIII, we can find Edward IV, who married Elizabeth Woodville, who was an untitled nobody, although her mother was a princess of Luxembourg. Edward and Elizabeth produced a bunch of children, including Edward V and Richard, Duke of York, the famous "Princes in the Tower," (widely presumed to have been murdered by their uncle Richard III), as well as Elizabeth of York, who married Henry VII. Elizabeth and Henry had several children as well, including (yes) Henry VIII.
Henry VIII, the serial marrier, took a number of commoner wives, all of whom were daughters of minor nobility. Anne Boleyn was the daughter of Sir Thomas Boleyn, Jane Seymour was the daughter of John Seymour, Katherine Howard was the daughter of Lord Edmund Howard and Catherine Parr was the daughter of Sir Thomas Parr. Here we see, I think, a little bit more of an analogy to the origins of Catherine Middleton, accepting that the Duchess of Cambridge's father is "in trade" and Henry's many fathers-in-law were members of the landed nobility, however minor. But if we are looking for a royal bride with a dad who has no titles and a mom with no recent links to the nobility, it seems to me that Catherine is sui generis, even if she and her husband are distantly related. Let's face it: a lot of people who live in England are related via the Edwards (I and III): it's a tight little island. In any case, in general, genetically speaking, inbreeding discouraged, outbreeding recommended. And best wishes to the parents and the bundle of joy.
Update: yet another newspaper article with a mistake that could easily have been corrected had the reporter just checked a fact. This story asserts that baby Cambridge will be Queen Elizabeth II's (and Prince Philip's--why does he always get left out?) fourth great-grandchild. No--she or he will be number three. Peter and Autumn Phillips, son and daughter in law of Princess Anne, have two daughters. None of the Queen's other grandchildren have children that we know of. Only three of them are old enough to be married (Harry, Eugenie, and Beatrice). Great-grandchild number four will be the child of Zara Tindall and her husband; Ms. Tindall is also the child of Princess Anne. I realize that I sound like I'm nitpicking. But really--if a reporter is going to write a story, she or he ought to get the facts right. (Normally, I wouldn't pay so much attention, but I just finished an article on cognatic succession in the European monarchies, so I've been learning who's related to whom, and who follows whom in line, and all that).