then great civilizations, and Thales visited the neighbouring civilizations, Egypt, Mesopotamia, Crete, and Phoenicia. In Egypt, geometry was advanced as a means of separating agricultural fields. Thales, though, advanced geometry with his abstract deductive reasoning reaching universal generalizations. Proclus, a later Athenian philosopher, attributed the theorem now known as Thales's theorem to Thales. He is also known for being the first to claim that the base angles of isosceles triangles are equal, and that a diameter bisects the circle. Thales visited Sardis, as many Greeks then, where astronomical records were kept and used astronomical observations for practical matters (oil harvesting). Thales was widely considered a genius in ancient times and was revered as one of the Seven Sages of Greece. Most importantly, what marks Thales as the first philosopher is the posing of the fundamental philosophical question about the origin and the substance of the world, while providing an answer based on empirical evidence and reasoning. He attributed the origin of the world to an element instead of a divine being. Our knowledge of Thales' claim derives from Aristotle. Aristotle, while discussing opinions of previous philosophers, tells us that "Thales, the founder of this type of philosophy, says the principle (arche) is water." What he meant by arche, is a matter of interpretation (might be the origin, the element, or an ontological matrix), but regardless of the various interpretations, he conceived the world as One thing instead of a collection of various items and speculated on the binding/original elements. Another important aspect of Thales' philosophy is his claim that everything is full of gods. What he meant by that is again a matter of interpretation, that could be from a theistic view to an atheist one. But the most plausible explanation, suggested by Aristotle, is that Thales is advocating a theory of hylozoism, that the universe, the sum of all things that exist, is divine and alive. Lastly, another notable claim by Thales is that earth "rests on water"- maybe that was a conclusion after observing fish fossils on land. Anaximander Anaximander (610–546 BCE), also from Miletus, was 25 years younger than Thales. He was a member of the elite of Miletus, wealthy and a statesman. He showed interest in many fields, including mathematics and geography. He drew the first map of the world, was the first to conclude that the earth is spherical, and made instruments to mark time,