By then the Roman Empire was officially Christian.
Before the Muslim onslaught people forget that the Zoroastrian Persian/Parthian empire over ran and destroyed many of the Greco-Roman cities before the emperor Heraclius defeated them in what some historians called the world's first Crusade. The Zoroastrians had taken the relic of the True Cross as a war trophy when they looted Jerusalem and destroyed the church that was atop the temple mount.
The Muslims took advantage of this weakness from the war the Romans and Parthians fought to first take over the defeated Persians and then take the Middle East from the weakened Romans.
So, more likely the deceased was a member of one of the Christian sects that did not conform to the Council of Nicea.
Justinian 1 reconquered and ruled over the some of the old Roman terretories.
Constatniople would be the seat of civilization and culture until it was conquered by the Turks who would rule until WWI.
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