It can be argued that if Euclid is the father of Geometry that Hippocrates of Chios could be considered the grandfather of geometry. Hippocrates was born about 410 BC in Chios, Greece and died about 410 BC. He was a Greek merchant turned geometer who compiled the first known work on the elements of geometry. .
I chose to write about Hipprocates because the little-known people who contribute to the works of others should always be recognized. He was very interested in math and astronomy and he was one of the greatest mathematicians of ancient times.
Hippocrates was the greatest geometer of antiquity (relating to ancient times) but was "stupid and incompetent in the business of everyday life" as quoted by Aristotle. According to tradition, he lost his property because of his stupidity. Due to an unfortunate chain of events his life changed. One theory is that Hippocrates was a successful merchant until he was captured by pirates near Byzantium. The other theory is that dishonest customs men threatened him with imprisonment and they stole everything he owned. It is then believed Hippocrates went to Athens to try to recoup his losses in a court of law. While waiting for any action to be taken against the men, he had a lot of spare time. Hippocrates attended lectures and classes on math and philosophy and took up teaching to support himself. He became so successful that he was able to open up his own school and teach.
Hippocrates became interested in math and astronomy late in life. He believed that there was only one comet, which was a planet that appeared at long intervals. He also believed that the comet's tale was a type of mirage caused by the comet taking up moisture when it neared the sun. Hippocrates created a similar theory to explain the appearance of the galaxy.
According to Notable Mathematicians from Ancient times to the Present, by Robyn v. Young, she states that "Hippocrates is believed to have been greatly influenced by the Pythagorean School of Mathematics, named after the famous Greek mathematician and philosopher, Pythagoras.