Thomas Augustine Arne (1710-1778) was the son of a well-to-do artisan from Covent Garden in London. The future composer received legal training and began to practice that profession, but found that he preferred music instead. He started studying and attending musical events in disguise and managed enough early success to survive the explosion that came when his father found out.
Arne had his breakout year as a composer in 1740 with two major state-sponsored hits. The first was his musical setting of a masque written by Congreve, The Judgment of Paris. The success of this work led to Arne's being engaged by Frederick, Prince of Wales, to write music for a new masque, Alfred, that the Prince wished to stage to honor the accession of his father, King George I, to the British throne and to celebrate the birthday of Princess Augusta. Alfred was performed at Cliveden House in Maidenhead, the residence of Prince Frederick, in 1740. "Rule, Britannia!" was the stirring finale of the masque, and it was acclaimed from the start. The text was written by James Thompson (1700-1748).
"Rule, Britannia!" was not heard in London until 1745, but from its first performance there it became nearly universally known and loved. The Jacobite opponents of the Hanoverian dynasty even attempted to co-opt the song by writing their own words to its infectious, Handelian tune. In practice, the song is known primarily through its rousing refrain -- the part that actually begins with the words "Rule, Britannia!" The late Peter Pears once recorded the whole melody with all its several verses, revealing that in toto this famous song is actually pretty tedious.
But the good bits are still beloved by patriotic Britons who like to remember when the Royal Navy really did rule the waves. "Rule, Britannia!" still maintains its status as the favorite patriotic air of the British people and as an unofficial second national anthem.