Mountbatten was German.
Yes, but that was not Phillip’s original name. And Lord Mountbatten was already an English citizen IIRC.
Lord Mountbatten was a British Naval Officer and Supreme Allied Commander, SE Asia during WWII:
Admiral of the Fleet Louis Francis Albert Victor Nicholas Mountbatten, 1st Earl Mountbatten of Burma, was a British naval officer and statesman, an uncle of Prince Philip, Duke of Edinburgh, and second cousin once removed of Queen Elizabeth II. During the Second World War, he was Supreme Allied Commander, South East Asia Command. He was the last Viceroy of India and the first Governor-General of independent India.More at Wikipedia