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In 2002.
Queen Elizabeth II celebrated her Golden Jubilee in July 2002.
No, the term 'golden jubilee' is a common noun, a word for a golden jubilee of any one or any kind.
A proper noun is the name of a specific golden jubilee, such as The Golden Jubilee of Queen Elizabeth II.
Buckingham Palace in the City of Westminister
Queen Elizabeth II celebrated the Golden Jubilee in 2002, 50 years since her accession to the throne in 1952.