Yes, and just to add to what everyone has already contributed: Prince Philip's mother, Princess Alice of Battenburg, is the daughter of Princess Victoria of Hesse whose mother was Princess Alice of the United Kingdom, a daughter of Queen Victoria. Princess Alice of the U.K. married
Louis (or Ludwig) IV, Grand Duke of Hesse. Their oldest daughter, Princess Victoria of Hesse, married her father's first cousin, Prince Louis of Battenberg who was an officer in the Royal Navy. During WWI, they changed their name to Mountbatten. Prince Philip's mother (Alice) and his Uncle (Lord Louis Mountbatten) were two of the children of Princess Victoria of Hesse and Louis of Battenberg. Therefore, most likely, Lord Louis Mountbatten was named for both his father (Louis) and his grandfather, Louis (Ludwig) IV of Hesse. And thereby the name was passed down.
http://img11.hostingpics.net/pics/242503PrinceandPrincessLouisofHesseDarmstadtJuly1862u.png Princess Alice of U.K. & Louis IV Grand Duke of Hesse
Unfortunately Princess Alice lost a hemophiliac son, Friedrich 'Frittie' who fell out of a window and died from internal bleeding; she lost another young daughter from typhoid fever which she then also contracted and died from; in addition two other daughters (the ill-famed Tsarina) Alexandra, and Elizabeth married into Russian royalty/nobility and were killed in 1918 during the Russian Revolution.
A must read book:
Victoria's Daughters, by Jerrold M. Packard (excellent history and revealing insight into the relationships between Queen Victoria and her daughters and their marriages).
http://www.goodreads.com/book/show/1695841.Victoria_s_Daughters
http://2.bp.blogspot.com/-dZikRSn_e...4B/s1600/07340de0c1a7e7e526b91ca6c59bc736.jpg
Princess Victoria of Hesse
The current British Prince Edward, Duke of Wessex's godfather, Louis Prince of Hesse and by Rhine, is the son of Ernest Louis, the eldest son of Alice of the U.K., and Louis (Ludwig) IV Grand Duke of Hesse (thereby Ernest is also the brother of Princess Victoria of Hesse, whose daughter Princess Alice is the mother of Prince Philip -- so Ernest is Prince Philip's great-uncle, and Louis Prince of Hesse and by Rhine is Prince Philip's cousin on his mother's side).
https://upload.wikimedia.org/wikipedia/en/7/75/ErnstLouisHesse.jpg
Ernest Louis, Grand Duke of Hesse
Prince Philip's mother, Princess Alice of Battenburg married into the Greek royal family. Her husband Prince Andrew, was the son of George I of Greece who had been appointed to the Greek throne, but was Danish and not a native of Greece. Therefore, Prince Philip's ancestral background is Danish and German. The English ancestry for Prince Philip is not strictly by blood since his great-great-grandmother is Queen Victoria whose father, Prince Edward Duke of Kent, was the fourth son of King George III of Great Britain, who had heavy Germanic roots. Queen Victoria's father (Prince Edward) also married a German, Princess Victoria of Saxe-Coburg-Saalfeld, a widow with two children. Queen Victoria (apparently named after her mother, was an only child). And as we know, Queen Victoria also married a German, Prince Albert of Saxe-Coburg-Gotha.
Meanwhile Queen Victoria's father's mother, Sophia Charlotte of Mecklinburg-Strelitz, the wife of King George III, had German ancestry on her father's side and Portuguese with some African roots on her mother's side. Known as Queen Charlotte, she was a very beloved Queen. The current Buckingham Palace was called the Queen's House after her, when King George III gave it to her as a gift.
Prince Philip was born at Windsor Castle. His mother, Princess Alice of Battenburg, was congenitally deaf and diagnosed with schizophrenia at age 30. Perhaps it was her mental illness which caused some of her eccentricities; she eventually founded an order of Greek Orthodox nuns. Due to his father having been overthrown and exiled, Prince Philip led a peripatetic life from a young age, but he's always seemed to have a sunny, robust temperament in contrast to the melancholy his parents suffered from.
Prince Philip and Queen Elizabeth are third cousins via sharing the same great-great-grandmother in Queen Victoria, on Elizabeth's father's side and Philip's mother's side. As well, Philip and Elizabeth are second cousins once removed, as Christian IX of Denmark was Queen Elizabeth's great-great-grandfather through her grandfather (George V's) mother, Alexandra of Denmark (who married King Edward VII). And via Prince Philip's grandfather on his father's side, George I of Greece, who was Alexandra of Denmark's brother.
https://www.thoughtco.com/queen-elizabeth-ii-and-prince-philip-3530296
Note that Christian IX of Denmark had largely German and some Danish roots. His children married into many European royal families, so that most current European monarchs are descended from Christian IX. All of this inbreeding was not a great practice. It led to hemophilia, porphyria, mental illness and some unattractive physical traits. Queen Elizabeth's mother had Scottish ancestry so that was a good pairing that did not involve inbreeding. As we know, Diana Princess of Wales also has more English ancestry than does Prince Charles.
It's a good thing that British royals marrying into other European royal families is no longer a widespread practice. It's great that Prince William married a commoner and that Prince Harry may well do so too. Kate Middleton's ancestry is British on both sides -- Her father, Michael Middleton's ancestral family is from Yorkshire, and they were solicitors for about 150 years. Michael is also distantly related via a great-grandfather, to former British Prime Minister Neville Chamberlain. His father, Peter Middleton, was a commercial pilot who also served as an RAF officer and fighter pilot during WWII.
Coincidentally, Peter Middleton was Prince Philip's co-pilot in 1962 during a two-month tour of South America! In addition, Kate's father Michael, is a direct descendant of King Edward III of England!! So in some respects, not so 'common' after all.
Kate's mother's maiden name is Goldsmith. Carole Goldsmith Middleton's father, Ronald Goldsmith, was a builder. Her mother, Dorothy Harrison, is descended from poor working class labourers in Sunderland and County Durham. Both parents had Jewish ancestors (there is some *Sephardic Jewish antecedents in Carole's family, but that heritage has been downplayed and in some quarters, debunked). Carole Middleton's parents were neither raised in nor practiced the Jewish religion. *Sephardic Jews originate from North Africa.
More notably, Carole Middleton is descended from Elizabeth Plantagenet, the illegitimate daughter of King Edward IV of England. In addition, Carole has Scottish antecedents through Elizabeth Plantagenet, who are related to ancestors of Queen Elizabeth's mother, Elizabeth Bowes-Lyon.
With this very British and very interesting background on both sides of her family, how can Kate be deemed 'common'? From looking down on her maternal grandmother's hardy, working class background?
It has been suggested that Duchess Kate's blood kinship with Queen Mother Elizabeth Bowes-Lyon, is the reason why Kate wore the Queen Mother's tiara when she wed Prince William. And btw, this blood connection means that Duchess Kate and Prince William are 11th cousins once removed. But that's far enough removed to not be a problem.