Known as "The Atomists"
They believed that if matter was continuously cut in half that eventually you would get to a particle that was "uncuttable". Democritus was the first person to use the word atom.
In Greek Atomos = uncuttable
Well Established Philosopher
He believed that all matter was made of variable combinations of five different elements:
Earth, Air, Fire, Water, and Ether.
The philosophers put forth their ideas at relatively the same time and because they were philosophers, not scientists, neither had any scientific evidence to support their ideas; still Aristotle's theory gained respect and "The Atomists" were ridiculed.