The model of light that states that it is composed of millions of particles is the particle theory of light, also known as the corpuscular theory of light. This theory was first proposed by Isaac Newton in the 17th century.

However, it's important to note that:

* Modern physics has largely replaced the corpuscular theory with the wave-particle duality of light. This theory states that light exhibits both wave-like and particle-like properties.

* The particles of light are called photons, which are not "millions" of particles, but rather quantized packets of energy.

While Newton's particle theory was influential, it couldn't explain phenomena like diffraction and interference, which are best explained by the wave nature of light. The modern understanding of light combines both wave and particle aspects.