Greek polymath Eratosthenes of Cyrene was a mathematician, poet, geographer, music theorist, and astronomer. He also served as the Library of Alexandria’s chief librarian. He was also the first to calculate the Earth’s circumference and the tilt of the Earth's axis. Nicknamed Pentathlos, he also invented many scientific terms.
Strabo was a Greek philosopher, geographer, and historian. He is best remembered for his work Geographica, an encyclopedia of geographical knowledge. Written in Greek during Strabo's time, Geographica holds great historical significance as it houses a descriptive history of places and people from different regions. Among his descriptions were places like the city of Alexandria and India.
Pytheas was a Greek geographer, astronomer, and explorer. Best known for his legendary voyage to northwestern Europe, Pytheas was the first scientific visitor to witness and describe polar ice, the Arctic, and the Germanic and Celtic tribes. He is also the first explorer to see and describe the midnight sun.

Posidonius was a Greek astronomer, astrologer, politician, historian, mathematician, geographer, and teacher. Widely regarded as the most learned man of his generation, Posidonius took genuine interest in natural history and natural science. He worked towards spreading Stoicism to the Roman world through his personal lectures and writings. Also a philosopher, Posidonius’ works have influenced the works of several subsequent writers.

Hecataeus of Miletus was a Greek geographer and historian best remembered for his composition of historical and geographical works. Regarded as the first known Greek historian, Hecataeus was one of the first classical authors to write about the Illyrian and Celtic peoples. Hecataeus of Miletus is also considered the Father of Geography.

Dicaearchus was a Greek philosopher, author, and geographer who studied under Aristotle in the Lyceum. Dicaearchus wrote on subjects, such as geography, politics, philosophy, and ancient Greek poets. Very few of his works have survived and among them, Life of Greece is considered the most prominent work of his career.

Agatharchides was a Greek geographer and historian who flourished during the second century BC. He was also a prominent political figure and served as a guardian to one of Ptolemy VIII's son. Agatharchides is also remembered for his literary works such as On the Erythraean Sea and Affairs in Asia.