Attalus of Rhodes was an ancient Greek grammarian, astronomer

Astronomer

An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...

, and mathematician

Mathematician

A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....

, who lived in Rhodes

Rhodes

Rhodes is an island in Greece, located in the eastern Aegean Sea. It is the largest of the Dodecanese islands in terms of both land area and population, with a population of 117,007, and also the island group's historical capital. Administratively the island forms a separate municipality within...

 in the 2nd century BC, and was a contemporary of Hipparchus

Hipparchus

Hipparchus, the common Latinization of the Greek Hipparkhos, can mean:* Hipparchus, the ancient Greek astronomer** Hipparchic cycle, an astronomical cycle he created** Hipparchus , a lunar crater named in his honour...

. He wrote a commentary on the Phaenomena of Aratus

Aratus

Aratus was a Greek didactic poet. He is best known today for being quoted in the New Testament. His major extant work is his hexameter poem Phaenomena , the first half of which is a verse setting of a lost work of the same name by Eudoxus of Cnidus. It describes the constellations and other...

. Although this work is lost, Hipparchus cites him in his Commentary on the Phaenomena of Eudoxus and Aratus. Attalus sought to defend both Aratus and Eudoxus

Eudoxus of Cnidus

Eudoxus of Cnidus was a Greek astronomer, mathematician, scholar and student of Plato. Since all his own works are lost, our knowledge of him is obtained from secondary sources, such as Aratus's poem on astronomy...

against criticisms from contemporary astronomers and mathematicians.