Name the title and the authors of the stage musical work named after a town in southwestern England?

The stage musical work named after a town in southwestern England is indeed "The Pirates of Penzance," created by the renowned duo W.S. Gilbert and Arthur Sullivan. This comic opera, often referred to as an operetta, is celebrated for its witty libretto by Gilbert and its delightful music by Sullivan. The setting of the story is the picturesque coastal town of Penzance in Cornwall, England, which at the time of the operetta's creation in the late 19th century, was a rather peaceful seaside resort. The humorous contrast between a band of boisterous pirates and such a tranquil location was part of Gilbert's signature "topsy-turvy" style, where absurdities are taken to their logical conclusions.

Gilbert and Sullivan were a hugely successful Victorian-era theatrical partnership, collaborating on fourteen comic operas between 1871 and 1896. Their works are considered significant for influencing the development of modern musical theatre, blending memorable melodies with sharp satire and engaging plots. "The Pirates of Penzance" showcases their characteristic blend of romance, comedy, and a gentle mocking of British society and strict Victorian rules, as seen in the much-parodied "Major-General's Song."

Interestingly, "The Pirates of Penzance" was the only Gilbert and Sullivan opera to have its official premiere in the United States, debuting in New York City on New Year's Eve in 1879. This unusual decision was a strategic move to secure copyright protection in America, as unauthorized "pirated" productions of their previous hit, "H.M.S. Pinafore," had been rampant due to the lack of international copyright laws at the time. To secure British copyright, a single, hurried performance was also staged in Paignton, England, the day before the New York premiere.

The plot itself revolves around Frederic, a young man mistakenly apprenticed to a band of tender-hearted pirates until his 21st birthday. A comedic twist arises when he discovers he was born on February 29th, a leap year, meaning he is technically only five years old and thus bound to the pirates for many more decades. This clever use of a leap year birthday is a prime example of the ingenious and often paradoxical humor that made Gilbert and Sullivan's operettas so enduringly popular, and why "The Pirates of Penzance" remains a beloved classic today.