Colchis was a scene of the protracted rivalry between the Eastern Roman/Byzantine and Sassanid empires, culminating in the Lazic War from 542 to 562. The war resulted in the decline of Lazica, and the Abasgi in their dense forests won a degree of autonomy under the Byzantine authority. During this era the Byzantines built Sebastopolis in the region. Their land, known to the Byzantines as Abasgia, was a prime source of eunuchs for the empire until Justinian I (527-565) forbid the castration of boys. The people were pagan and worshiped groves and trees until a mission sent by the emperor Justinian I around 550 converted the people to Christianity and built a church. However bishop Stratophiles of Pytius attended the Council of Nicaea as early as 325. Byzantines constructed defensive fortifications that may have partially survived to this day as the Kelasuri Wall.