|Ludwig van Beethoven|
Piano Sonata No. 14 aka "Moonlight Sonata"
by Ludwig van Beethoven
Ludwig van Beethoven is the fifth Artist (Mozart, Handel, Bach?) on this list to produce a tune that is remembered "today" by a large Audience. The Moonlight Sonata, with a century of non-stop public domain levels of exploitation by modern Advertisers, is intimately familiar to any living human, even if they only know it as the refrain from a local jewelry store ad.
To give you an idea of how powerful Piano Sonata No. 14/Moonlight Sonata actually is, you can measure it's popularity vs EVERY mention of the proceeding Artist, Joseph Haydn. Through 1940, the song was more frequently mentioned then Joseph Haydn himself. Joseph Haydn was publishing 20 years earlier, so clearly Beethoven is reaping the benefit of a larger Audience for his published works and public performances.
One of the issues I imagined Beethoven dealt with in the early 19th century was contrasting a likely Audience preference for symphonies with a lower-key but potentially as lucrative trade in shorter, simpler pieces of music. I would guess that Beethoven tried to balance the demands.