 One important figure during this time was Empedocles (480 BC) who viewed the blood as the "innate heat" which he acquired from previous folklore.He also argued that the heart was the chief organ of both the vascular system and the pneuma (this could refer to either breath or soul; it was considered to be distributed by the blood vessels).Many medical texts by various authors are collected in the "Hippocratic Corpus", none of which can definitely be ascribed to Hippocrates himself.