"The William Tell Overture" is the overture to the opera "William Tell", whose music was composed by Gioachino Rossini (29 February 1792 – 13 November 1868). "William Tell" premiered in 1829 and was the last of Rossini's 39 operas, after which he went into semi-retirement (he continued to compose cantatas, sacred music and secular vocal music). The overture is in four parts, each following without pause.

There has been repeated use (and sometimes parody) of parts of this overture in both classical music and popular media. One of the most frequently used pieces of classical music in American advertising, the overture (especially its finale) appears in numerous ads, with psychologist Joan Meyers-Levy suggesting that it is particularly suitable for those targeting male consumers.

It was the theme music for "The Lone Ranger" in radio, television and film. It was also used for the British television series "The Adventures of William Tell".

Amongst the films which feature the overture prominently is Stanley Kubrick's "A Clockwork Orange". The opening phrase of the Finale was used in "The Princess Diaries".

Rossini didn't write the overture until the last minute. The premiere of the opera was approaching, and he needed something. So he dug into his past works. There he found an opera he'd written 14 years earlier, "Elizabeth, Queen of England." He recycled parts of it into “The William Tell Overture.”

More Info: en.wikipedia.org