Early in the 18th century Italian opera began to be imported into England, prompting a peculiarly British reaction,
the so-called ballad opera. Far and away the most famous of these is John Gay
's "THE BEGGAR'S OPERA"
a political and social satire set to music, which made it's first appearance in London in 1728.
Gay took the melodies of popular broadside ballads, such as "Over The Hills And Far Away"
as well as some operatic melodies and added words to fit the plot of the play, setting it all within an operatic framework.
By the end of the century the genre had developed into early "high" ballad opera, a style which would eventually be combined
with the "low" tradition started by Gay, to produce the light comic operas, or operettas, of Offenbach in Europe and
Gilbert & Sullivan
in Britain, which are really a combination of Grand Opera and Victorian Music Hall
and mark the beginnings of modern musical theatre