Septimius Severus, also known as Severus, was Roman emperor from 193 to 211. Severus was born in Leptis Magna in the Roman province of Africa. As a young man he advanced through the cursus honorum—the customary succession of offices—under t...

The main desire of Ptolemy in writing his Almagest is to explain and account for the motions of the apparently erratic celestial beings in terms of perfect and circular motions. In doing so he introduces the epicyclic (which states that the...

Commodus was Roman Emperor from 180 to 192. He also ruled as co-emperor with his father Marcus Aurelius from 177 until his father's death in 180. His name changed throughout his reign; see changes of name for earlier and later forms. His ac...

According to the Christian father Origen, Celsus was a 2nd-century Greek philosopher and opponent of Early Christianity. He is known for his literary work, The True Word, which survives exclusively in Origen's quotations from it in Contra C...

Ardashir I or Ardeshir I, also known as Ardashir the Unifier, was the founder of the Sasanian Empire. He was the ruler of Estakhr since 206, subsequently Pars Province since 222, and finally "King of Kings of Sasanian Empire" in 224 with th...

Caracalla, formally known as Antoninus, was a Roman emperor from AD 198 to 217. A member of the Severan Dynasty, he was the eldest son of Septimius Severus and Julia Domna. Caracalla reigned jointly with his father from 198 until Severus' d...

Valerian, also known as Valerian the Elder, was Roman Emperor from 253 to 260 AD. He was taken captive by Sassanian Persian king Shapur I after the Battle of Edessa, becoming the first Roman Emperor to be captured as a prisoner of war, caus...

Diogenes Laërtius was a biographer of the Greek philosophers. Nothing is definitively known about his life, but his surviving Lives and Opinions of Eminent Philosophers is a principal source for the history of ancient Greek philosophy....

Marcus Julius Philippus also known commonly by his nickname Philip the Arab, also known as Philip, was Roman Emperor from 244 to 249. He was born in present-day Syria to a Syrian father, and went on to become a major figure in the Roman Emp...

Plotinus was a major philosopher in the ancient world and is widely considered the father of Neoplatonism. Much of our biographical information about him comes from Porphyry's preface to his edition of Plotinus' Enneads. His metaphysical wr...

Aurelian was the 44th Emperor of the Roman Empire from 270 to 275. Born in humble circumstances, he rose through the military ranks to become emperor. During his reign, he defeated the Alamanni after a devastating war. He also defeated the...

Mani was the prophet and the founder of Manichaeism, a gnostic religion of Late Antiquity which was once widespread but is now extinct. Mani was born in or near Seleucia-Ctesiphon in Parthian Babylonia, at the time still part of the Parthia...

Shapur I the Great was the second shahanshah (king of kings) of the Sasanian Empire. The dates of his reign are commonly given as 240/42 – 270/72, but it is likely that he also reigned as co-regent (together with his father) prior to his fa...

Zenobia was a 3rd-century Queen of the Palmyrene Empire in Syria, who led a famous revolt against the Roman Empire. The second wife of King Septimius Odaenathus, Zenobia became queen of the Palmyrene Empire following Odaenathus' death in 26...

Gaius Aurelius Valerius Diocletianus was Roman Emperor from 20 November 284 to 1 May 305. Diocletian was one of the few emperors of the third and fourth centuries to die naturally, and the first in the history of the empire to retire volunt...