On 20th November 1947 Her Royal Highness Princess Elizabeth (now Queen Elizabeth II) married Lieutenant Philip Mountbatten (Prince Philip, Duke of Edinburgh) at Westminster Abbey.

Why is Queen Elizabeth II’s husband a prince rather than a king?

In the British monarchy, the husband of a female monarch does not have any recognized special status, rank, or privileges.

Prince Philip was a prince from birth. He is the son of Prince Andrew of Greece and was born Prince of Greece and Denmark. Upon his marriage to then-Princess Elizabeth in 1947, Philip was given the title "Duke of Edinburgh, Earl of Merion, and Baron Greenwich," and was made a Knight of the Garter. (He became a British citizen around this time and renounced his Greek and Danish titles). Elizabeth II was coronated in 1953, and in 1957, she granted Philip the title "Prince of the United Kingdom."

What is Queen Elizabeth’s surname?

The Queen does not normally use a surname (she doesn’t need a passport or a driving licence for example), but on the few occasions where it has been necessary, i.e. when serving with the ATS during World War II, she has used the surname ‘Windsor‘.
(source: www.royal.gov.uk)

The British royal family changed their last name from Saxe-Coburg-Gotha to Windsor in 1917. Why? World War One broke out in 1914 and anti-German sentiment was its height in 1917. In protest, King George V renounced all the German titles belonging to him and his family and adopted the name of his castle, Windsor.

From 8 February 1960, all The Queen’s descendants who do not bear the "style, title or attribute of HRH, and the titular dignity of Prince or Princess" have the name of Mountbatten-Windsor. (Mountbatten as Prince Philip’s surname).