Mirian III

Mirian III
King of Iberia
Reign284–361
PredecessorAspacures I
SuccessorSauromaces II
Bornc.277 or 258
Sasanian Iran
Died361 (aged 83–84)
Mtskheta, Iberia
Burial
SpouseAbeshura
Nana
IssueRev II
Aspacures II
Anonymous daughter
DynastyChosroid dynasty
ReligionGeorgian Orthodox Church (from 326)
Zoroastrianism (before 326)

Mirian III (Georgian: მირიან III) was a king (mepe) of Iberia or Kartli (Georgia), contemporaneous to the Roman emperor Constantine the Great (r. 306–337). He was the founder of the royal Chosroid dynasty.

According to the early Medieval Georgian annals and hagiography, Mirian was the first Christian king of Iberia, converted through the ministry of Nino, a Cappadocian female missionary. Following the Christianization of Iberia, he is credited with having established Christianity as his kingdom's state religion and is regarded by the Georgian Orthodox Church as a saint and was canonized as Saint Equal to the Apostles King Mirian (Georgian: წმინდა მოციქულთასწორი მეფე მირიანი).

Traditional chronology, in line with Prince Vakhushti's Description of the Kingdom of Georgia, assigns to Mirian's reign—taken to have lasted for 77 years—the dates 268–345, which Professor Cyril Toumanoff changed to 284–361. He was also known to the contemporary Roman historian Ammianus Marcellinus and the medieval Armenian chronicles.