Classical physics refers to physical concepts that predate newer, more comprehensive, or widely applicable theories.
Energy, as well as matter, have been regarded as independent concepts throughout classical physics
Classical physics includes Newtonian mechanics and thermodynamics, particularly Maxwell's electromagnetic concept.
Quantum physics is the branch of classical physics that study of matter and energy at the microscopic level.
It's an elemental theory of physics that comes up with the explanation of the physical properties of nature on a very small scale.
In quantum, the dual nature of light means light can behave as a wave or particle is discussed.
Now as according to classical physics: When light is just a wave meaning “not quantum” likewise in the "ancient" way of thinking about physics without its duality and complexity.
The explanation of the properties of nature is at a large scale (macroscopic).