What unites the two churches is that both are against the EO communion, against the falsley so-called New Rome ie Constantinople, against its "Ecumenical Patriarch," and against the Eastern emperors.
Well, let's see:
1. It was the Roman Empire,
2. The Emperor moved the Capital to Byzantium,
3. It was decided that since it was the captial of the Roman Empire it should be called Rome,
4. But there was already a Rome that had existed for quite some time,
5. Therefore they called it "New Rome."
So it wasn't "so-called
" as if it were a fantasy... It really was
New Rome - first in the Political sphere, then in the religious.
Ecumenical Patriarch is a pre-schism term. Hate the emperors if you want - I don't care.