3rd-century Greek writers

Aelius Galenus or Claudius Galenus (; September 129 – CE), often anglicized as Galen () or Galen of Pergamon, was a Roman and Greek physician, surgeon, and philosopher. Considered to be one of the most accomplished of all medical researchers of antiquity, Galen influenced the development of various scientific disciplines, including anatomy, physiology, pathology, pharmacology, and neurology, as well as philosophy and logic.

Diophantus of Alexandria () (; ) was a Greek mathematician who was the author of the Arithmetica in thirteen books, ten of which are still extant, made up of arithmetical problems that are solved through algebraic equations.

Eusebius of Caesarea (30 May AD 339), also known as Eusebius Pamphilius, was a historian of Christianity, exegete, and Christian polemicist from the Roman province of Syria Palaestina. In about AD 314 he became the bishop of Caesarea Maritima.

Greco-Roman statesman and historian (c. 155–c. 235)

Irenaeus ( or ; ; ) was a Greek bishop noted for his role in guiding and expanding Christian communities in the southern regions of present-day France and, more widely, for the development of Christian theology by opposing Gnostic interpretations of Christian Scripture and defending orthodoxy. Originating from Smyrna, he had seen and heard the preaching of Polycarp, who in turn was said to have heard John the Evangelist.

Athenaeus of Naucratis (; or Nαυκράτιος, Athēnaios Naukratitēs or Naukratios; ) was an ancient Greek rhetorician and grammarian, flourishing about the end of the 2nd and beginning of the 3rd century AD. The Suda says only that he lived in the times of Marcus Aurelius, but the contempt with which he speaks of Commodus, who died in 192, implies that he survived that emperor. He was a contemporary of Adrantus.

Herodian or Herodianus (), sometimes referred to as Herodian of Antioch (c. 170 – c. 240), was a minor Roman civil servant who wrote a colourful history in Greek titled History of the Empire from Marcus onwards (τῆς μετὰ Μάρκον βασιλείας ἱστορία) in eight books covering the years 180 to 238. His work is not considered entirely reliable, although his less biased account of Elagabalus may be more useful than that of Cassius Dio. The origin of Herodian is contested in scholarship, popular hypotheses being Syria, Alexandria in Egypt and Asia Minor. However, he appears to have lived for a considera

Philostratus or Lucius Flavius Philostratus (; ; 170s – 240s AD), called "the Athenian", was a Greek sophist of the Roman imperial period. His father was a minor sophist of the same name. He flourished during the reign of Septimius Severus (193–211) and died during that of Philip the Arab (244–249), probably in Tyre.

thumb|Fragmentary statue base erected for Dexippus at Eleusis (I.Eleusis 656 = IG II² 3671) Publius Herennius Dexippus (; c. 210–273 AD), Greek historian, statesman and general, was an hereditary priest of the Eleusinian family of the Kerykes, and held the offices of archon basileus and eponymous in Athens.

3rd century Greco-Roman historian

Apsines of Gadara (; fl. 3rd century AD) was a Greek rhetorician. He was a native of the Hellenised city of Gadara, whose ruins stand today at the border of Jordan with Syria and Israel. Apsines went on to study at Smyrna and taught at Athens, gaining such a reputation that he was raised to the consulship by the emperor Maximinus. He was a rival of Fronto of Emesa, and a friend of Philostratus, the author of the Lives of the Sophists, who praises his wonderful memory and accuracy.

3rd-century Greek historian, orator, rhetorician and sophist

Agathemerus () was a Greek geographer who during the Roman Greece period published a small two-part geographical work titled A Sketch of Geography in Epitome (), addressed to his pupil Philon. The son of Orthon, Agathemerus is speculated to have lived in the 3rd century. Although little is known about Agathemerus historically, he lived after Ptolemy, whom he often quotes, and before the formation of Constantinople on the site of Byzantium by Constantine the Great in 328 AD, as he only refers to the city as Byzantium. From his speaking of Albion , it has been thought that he wrote not very long

ancient Greek mathematician (4th century AD)

ancient Greek historian