Hippasus

84. Hippasus of Metapontum was another Pythagorean, who held that there is a definite time which the changes in the universe take to complete and that the All is limited and ever in motion.

According to Demetrius in his work on Men of the Same Name, he left nothing in writing. There were two men named Hippasus, one being our subject, and the other a man who wrote The Laconian Constitution in five books; and he himself was a Lacedaemonian.