Heraclitus. Coloured historical artwork of the ancient Greek philosopher Heraclitus. He was born circa 535BC in Ephesus. He believed that everything was in a continual state of change driven by a constant tension between opposites. He also thought that the principle element was fire. Very little is known of Heraclitus' life and only some of the ideas from his book On Nature have survived. Diogenis Laertius wrote in 200AD that Heraclitus became disillusioned with the government of the city and went to live in the mountains. On returning with an ailment he apparently buried himself in a cow-stall in the hope that the warmth of the manure would cure him.