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.
One of the Seven Wise Men of Greece, Thales was a 6th-century mathematician who believed that the Earth was a flat disk floating on a huge ocean. Legend has it that he had predicted a solar eclipse that stopped a major battle and had also laid down several geometrical theorems.

Aristarchus of Samos was an ancient Greek mathematician and astronomer best known for being the first person to present the heliocentric model at a time when the geocentric theories of Ptolemy and Aristotle were considered conventional. Aristarchus of Samos even estimated the sizes of the Moon and Sun and is regarded as one of the greatest thinkers of all time.

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.

Archytas was an Ancient Greek astronomer, mathematician, philosopher, strategist, statesman, and music theorist. One of the most important and popular scientists of the Pythagorean school, Archytas is famous for founding mathematical mechanics. Also remembered as a dear friend of Plato, Archytas is also credited by Aulus Gellius with building the first self-propelled flying device which supposedly flew some 200 meters.

Berossus was a Babylonian writer, astronomer, and a priest of Bel Marduk. Berossus, who wrote in the Koine Greek language prevalent during the Hellenistic period, is claimed to have invented the semi-circular sundial by popular Roman architect and engineer Vitruvius.

Theon of Alexandria was a Greek mathematician and scholar. He is credited with editing and arranging Euclid's prominent work Elements. He also wrote commentaries on works by Ptolemy and Euclid. Theon of Alexandria's daughter Hypatia also went on to become a famed mathematician.

Greek philosopher and astronomer Heraclides Ponticus was the first to suggest the phenomenon of the rotation of the Earth, a concept that didn’t become a part of mainstream astronomy until after 1,800 years. Only fragments of his original writings have survived. He studied under Plato, and managed his academy in his absence.

Greek mathematician Hippocrates of Chios revolutionized geometry and inspired Euclid’s Elements. Initially a merchant, he was looted by pirates. Unsuccessful in bringing them to justice in Athens, he started studying math. He was the first to author a systematic textbook of geometry. He is also known for his work on astronomy.

Menelaus of Alexandria was a Greek astronomer and mathematician. Sphaerica, his only book to have survived in the form of an Arabic translation, deals with the geometry of the sphere and introduces the concept of spherical triangle. The Arabic version of the book was translated again by Francesco Maurolico, a 16th century mathematician and astronomer.

Conon of Samos was a Greek mathematician and astronomer best known for naming the constellation Coma Berenices. As a mathematician, Pappus credits Conon of Samos with the discovery of the spiral of Archimedes. Conon is also remembered for his friendship with the popular mathematician, Archimedes.

Ammonius Hermiae was a Greek philosopher and lecturer best remembered for delivering lectures on the works of imminent personalities like Aristotle, Plato, and Porphyry of Tyre. He also wrote commentaries on Platonic and Aristotelian works. Ammonius Hermiae is also credited with teaching several Neoplatonists like Olympiodorus of Thebes, Damascius, Simplicius of Cilicia, John Philoponus, and Asclepius of Tralles.

Byzantine theologian and historian Michael Glycas was from the Greek island of Corfu. Accused of conspiring against emperor Manuel I Komnenos, he was partially blinded and imprisoned but continued to write even while in prison. Verses from Prison and his chronicle remain his best-known works.