Or did they always call it classical music?
The term "classical music" was not coined until well after the classical era. Musicians of the classical era did consider their music to reflect the simplicity and clarity of classical Greece (5th to 4th c. BCE) compared to the more complex counterpoint of the Baroque era but like every era they simply considered their music to be modern or new music. Historians generally recognize and name eras after the fact. Classical music originally referred to what was considered the "golden era" of music from Bach to Beethoven but musicologists later narrowed the classical era to be from 1750-1800 but to the lay public classical refers to any Western art music from the earliest composed Western music to present (when I was in music school anyway: Beethoven was considered a transition composer between classical and romantic eras but now the classical era is considered to be 1750-1830 to include Beethoven).
My guess is that its in the same boat as what they call Chinese food in china(which would be just food) and they called it just music
