Here are some of the important events that gave us sheet music as we know it today. Years are given where known. Many were more general changes in the musical environment.
6th century BCE – musical notation handwritten in Greece
Musical terms established in Italy
12th century – German Lieder songs
12th century – French Chanson
1440 – Gutenburg press with moveable type
1457 – music engraving and publishing
1597 – Opera
mid 1700s – song collections
late 1700s – single song publications such as The Anacreontic Song
1793 – musical plays such as “The Children in the Wood”
1796 – Lithography
1840s – celebrity singing stars like Jenny Lind
1843 – the minstrel show begins in New York, selling sheet music
1848 – Stephen Foster is the first full-time professional song creator
1850s – full title pages
1850s – British music hall begins
1860s – cover illustrations
1861 – Civil War songs are significant
1866 – The Black Crook, first modern musical (?)
1877 – first sound recording made
1887 – color text on covers
1890s – photographs on covers
1890s – player piano rolls
1890s – ragtime music
1890s – song plugging begins
1892 – John Philip Sousa begins touring
1892 – After the Ball achieves high sheet music sales
1911 – Irving Berlin has a smash hit with “Alexander’s Ragtime Band”
1914 – ASCAP, enforced copyright, infused interest in song writing
1914 – piano rolls develop a style of their own
1917 – first jazz record
1927 – Showboat, first book musical (?)
1927 – The Jazz Singer, first talking picture
1929 – The great depression shook the music business
1935 – Swing, boogie-woogie and jive
Your additions and corrections are welcome.