Where was classical music originated?

Difficult question. The biggest inspiration for creating western music was religion. It was never birthed at a certain time but it evolved from the music that came before it. In the Vatican, throughout the early middle ages monks would sing in perfect fifths and would learn and sing by ear. It was Pope Gregory who is often credited as the man who first notated and simplified music. It was very raw and simplified but it allowed monks to read the music they were learning.

This evolved, more notes and note lengths were added and eventually evolved upon until the common score was created (with a bass and treble clef.) It was during this evolution that was called the medieval period of music, where most of the music being created was coming out of Italy.

After this came the Renaissance which is generally seen as being from 1400-1600 where music had evolved to be able to be played in small groups and notated easily. This is when countries such as France and Germany had their influence on the standard European music.

It wasn't until the birth of Bach as a composer that the rest of Europe had effect on classical music. He was German. From that point on, Germany, Italy and France were the biggest composers.

The classical era was born out of the Baroque era. It was birthed in primarily Germany and Italy.