The Ancient Greeks were a group of peoples who lived in the Mediterranean on the Peloponnesus and Attican Peninsulas. They were one group of peoples, but they all lived separately in places called city-states, each with their own ruler. One of the most influential city-states was Athens, which just so happened to also be the home to some of the most famous mathematicians, astronomers, and inventors to ever live. You will notice that there are some Ancient Greeks who are called 'philosophers' instead of scientist, mathematician, or astronomer. Many Ancient Greeks were philosophers, meaning "seekers and lovers of wisdom", but they were also scientists, mathematicians, and/or astronomers.

Note: On this website, the philosophers are generally called what they mostly specialized in or are famous for.