How were Queen Elizabeth II and Louis Mountbatten related?

Answer 1

Queen Elizabeth II's Great-Grandfather King Edward VII, and Lord Mountbatten's Grandmother Princess Alice, were brother and sister, children of Queen Victoria.

Queen Elizabeth referred to Lord Mountbatten as "Uncle Dickie".

Also, Lord Mountbatten's sister Alice married Prince Andrew of Greece, and they had a son Phillip, who married Queen Elizabeth II and became the Duke of Edinburgh, making the Queen and her husband 3rd cousins.

So....Queen Elizabeth and Prince Phillip both had Queen Victoria as a Gt-Gt-Grandmother.

Lord Mountbatten had Queen Victoria as his Gt-Grandmother.

The Mountbatten name was originally Battenberg, but was changed during the first World War because of hostilities with Germany.

The Royal Family stopped using their German names and titles in 1917.

The titles were inherited because of Queen Victoria's husband Prince Albert of Saxe-Coburg-Gotha.

Answer 2

They are not directly related, but they would be distant cousins.

They have a common ancester in Henry VII. He was Elizabeth's grandfather and is Prince Charles 15th great-grandfather.