Conversation so far:
When did Prince Philip, Duke of Edinburgh join the military?
After being educated in France, Germany and the United Kingdom, he joined the British Royal Navy in 1939, aged 18.
Did Prince Philip, Duke of Edinburgh serve in any war?
During the Second World War he served with distinction in the Mediterranean and Pacific Fleets.

Question: When did he retire from the forces?
Self-contained rewrite: When did Prince Philip, Duke of Edinburgh retire from the British forces?