Kan Rean

Rean, also known as Eran or Heran, was a Bulgar kan who ruled the Bulgars from around 488 to 521/525. Hungarian chronicles record his name as 'Great Lord', which can be translated as emperor. He launched a major westward offensive, extending south of the Danube, in 504 or, according to other sources, in 499, 501 or even 492–493. This offensive began immediately after Emperor Anastasius I rejected the peace and alliance treaty previously in force between Bulgaria and the Byzantine Empire, while Rean prepared an advance against Constantinople.

In 492, Scythians whom the Byzantines called Bulgars invaded Thrace. This attack is associated with Rean and the Bulgarian–Byzantine treaty terminated by Anastasius I in 491, which had been in force since the reign of the Byzantine emperor Zeno.

Between 491 and 499, or even as late as 501, Rean came from the east with a large army and conquered all of Dacia and Pannonia, encompassing the lands along the northern bank of the Danube, including present-day Romania and Hungary, as far as Austria.

In 493, the Bulgars living in Illyria and Thrace attacked and withdrew before being seen by anyone. This event is directly linked to the Bulgars who had settled in Lower Moesia during the lifetime of Maximinus I and to subsequent waves of settlement during the rule of the Bulgar Aspar and Emperor Zeno in the lands south of the Danube. As federates of the Roman Empire, they attacked Roman towns and fortresses in the southern Balkan Peninsula. This indicates that active military operations against Anastasius I began in 493 under the leadership of Rean, also known as Hrun III.