Acacius of Constantinople

Here we see the phenomenon of caesaropapism in Eastern religious affairs as Basilicus used his position as emperor to dictate religious doctrine and make religious appointments over the objections of church authorities.

While the bishops of Antioch, Jerusalem, Alexandria, and Ephesus supported Basilicus' encyclical, the two most important bishops in the whole Christian world, that's Patriarch Acacius of Constantinople and Pope Symmachus of Rome, fiercely opposed it.

Acacius, in particular, may have been afraid that Basilicus would try to replace him, and so he began plotting.

In an act of protest, Acacius ordered that all the churches in Constantinople be draped in black as if in mourning.