Constantine XI Dragaš Palaiologos, was the last reigning Byzantine Emperor, reigning as a member of the Palaiologos dynasty from 1449 to his death in battle at the fall of Constantinople. Following his death, he became a legendary figure in...

Irene of Athens, Byzantine empress (797-802). She served (780-90) as regent for her son, Constantine VI, and later was made (792) joint ruler. Devoted to the Orthodox Church, she bent most of her efforts to suppressing iconoclasm. In 797 Ir...

Justinian I, commonly known as Justinian the Great, was East Roman (Byzantine) Emperor from 527 to 565. During his reign, Justinian sought to revive the empire's greatness and reconquer the lost western half of the classical Roman Empire. O...

Flavius Valerius Leo (401–18 January 474), known in English as Leo the Thracian or Leo I, was a Byzantine Emperor who ruled from 457 to 474. He was known as Magnus Thrax (the "Great Thracian") by his supporters, and Macellus ("the Butcher")...

Theodosius also called Theodosius I and Theodosius the Great, was Roman Emperor from 379 to 395. Reuniting the eastern and western portions of the empire, Theodosius was the last emperor of both the Eastern and Western Roman Empire. After h...

Julian was Roman emperor from 361 to 363, as well as a notable philosopher and author in Greek. His rejection of Christianity, and his promotion of Neoplatonic Hellenism in its place, caused him to be remembered as Julian the Apostate by th...

Constantine, The Great was the 57th Emperor of the Roman Empire from 306, and the sole holder of that office from 324 until his death in 337. Best known for being the first Christian Roman emperor, Constantine reversed the persecutions of h...

Constantius I, commonly known as Constantius Chlorus, was Caesar, a form of Roman co-emperor, from 293 to 306. He was the father of Constantine the Great and founder of the Constantinian dynasty. As Caesar, he defeated the usurper Allect...

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...

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...

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...

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...

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...

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...

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...