Democritus (ancient Greek) invented atom theory, it was a bit different than what we know today but still impressive. Atoms were according to him all the same, they were always moving and made up everything. Since they were always moving there had to exist places without atoms. If I remember correctly there were also special soul-atoms that would leave the body upon death. Some of the presocratic philosophers really have interesting theories, especially the pluralists, though these theories are not mere stories.