It is generally accepted that music timelines are loosely based on composer's birthdays. But, as long as humanities majors in general, and musicologists (people who study music) specifically, have lips and vocal cords, they are going to debate period divisions! So,... keep in mind that the time divisions listed here are based loosely on European, Mediterranean, and Russian music history and are only guidelines.
Also, This is not the definitive list, but it will grow as time goes by. There are hundreds of musical instruments, events, composers, and inventions not listed here. It is only intended to cover some of the biggies. If you're interested in something in particular, you're going to have to do considerably more research.
Finally, remember that the century number indicates 100 years more than it actually is... for example 13th century is 1200-1299 or 19th century is 1800-1899.
** NOTES **
1. Composer dates are ordered by year of birth.
2. Major periods are boldface.
3. No period is absolutely defined and all periods overlap.
| Year (s) | Composer/Event |
| 1300 | Middle Ages begin... |
| 1300-1377 | Guillaume de Machaut (1300-1377), French composer |
| 1325 | Organ pedals are invented. |
| 1450 | Middle Ages end... |
| 1600 | Baroque Period begins... |
| 1750 | Baroque Period end... |
| 1750 | Classical Period begins... |
| 1820 | Classical Period ends... |
| 1820 | Early Romantic Period begins... |
| 1850 | Early Romantic Period ends... |
| 1820 | Romantic Period begins... |
| 1850 | Romantic Period ends... |
| 1850 | Late Romantic Period begins... |
| 1900 | Late Romantic Period ends... |
| 1890 | Impressionist Period begins... |
| 1900 | Contemporary Period begins... |
| 1914 | Hornbostel-Sachs system first published |
| 1920 | Impressionist Period ends... |
| 1961 | Hornbostel-Sachs system revised and re-published |