The second golden age in roman and christian art was brought about by the

The Macedonian emperors of the Byzantine Empire.

During the reign of Justinian (527-565), Byzantine art and architecture flourished.  As part of that flourishing, many churches were renovated, rebuilt, or newly built in Constantinople. The famous Hagia Sophia basilica, for instance, was rebuilt in glorious fashion after the previous structure had been destroyed in the Nika riots in 532.

After Justinian, there was political decline which let the arts lag also. Then, in the 8th century and lasting into the 9th century, there was the iconoclasm controversy.  "Iconoclasm" means destroying of icons or images in the church.  

But the Macedonian dynasty which came to power in 867, beginning with Basil the Macedonian, presided over a political and artistic renaissance in the Byzantine Empire.