But Democritus wasn't the only one with a theory...
Aristotle refuted that the atom even existed.
You see, all matter is made up of the four basic elements!
And so it remained...
And thus this theory prevailed for the next TWO THOUSAND years
Although Democritus' theory was remarkable, it was rejected by Aristotle, one of the most influential philosophers of Ancient Greece.
Aristotle believed that everything was a combination of the four elements: earth, fire, water, air. His theory was that a mass of incomprehensible size was everywhere; he called this 'hyle'. There was no separate 'particles' for each material, it was all one.
Democritus had no way to disprove Aristotle. Remember, these theories were based on thoughts and opinions. They were philosophers, not scientists. So Aristotle's theory was widely accepted for the next 2,000 years until science would prove Democritus right!