You ought to read “Upon this Rock” by Steve Ray. He goes over all of the Church Fathers, in one section focusing particularly on the
Eastern Fathers, to show the teachings regarding the papacy that were present in the early Church.
As far as the Filioque is concerned, it is very, very important that you look not so much at the specific words and definitions that the Fathers used about it, but rather at the concepts they are trying to convey.
For example, Roman Catholic theology has for centuries declared that Christ had two wills, whereas Oriental Orthodox theology declared Christ to have one will. Looking at the words, there was a clear disagreement. Yet the two groups have come to realize after all this time that the two sides are actually saying the same thing. They are using different language to describe it, but their meaning - the concept of Christ that they hold - is the same.
The reason that this tends to be a problem is because for some reason which I don’t understand at all, Eastern Christians often tend towards a particular sort of stubbornness when it comes to discussing theological points. I don’t want to go asserting stereotypes, it’s just something that anyone who’s interacted with them for some time can’t help but notice. It led Thomas Aquinas to say:
"Hence also the Greeks themselves recognize that the procession of the Holy Ghost has some order to the Son. For they grant that the Holy Ghost is the Spirit “of the Son”; and that He is from the Father “through the Son.” Some of them are said also to concede that “He is from the Son”; or that “He flows from the Son,” but not that He proceeds;
which seems to come from ignorance or obstinacy. For a just consideration of the truth will convince anyone that the word procession is the one most commonly applied to all that denotes origin of any kind. For we use the term to describe any kind of origin; as when we say that a line proceeds from a point, a ray from the sun, a stream from a source, and likewise in everything else. Hence, granted that the Holy Ghost originates in any way from the Son, we can conclude that the Holy Ghost proceeds from the Son. "
I really recommend you read the entire article:
newadvent.org/summa/1036.htm#2
I have seen discussions between Catholics and Orthodox wherein the Catholic will essentially at one point say, “So you believe that X is true,” and the Orthodox fellow will say, “Yes,” and the Catholic will say, “Well I believe the very same thing, but I use this other word instead to say that,” and the Orthodox fellow will simply not accept it. The Catholic will agree with the Orthodox’s position, and he’ll say he’d had no problem using those words to explain it, it just so happens that the traditional way to say that in Latin theology is with different words, and the Orthodox will declare the Catholic’s point of view heretical. I’m not singling out Orthodox here, btw, as it happens with Eastern Catholics all the time as well. And certainly there are Eastern Christians for whom this is not the case. It just seems to be the case frequently.
It’s just really too bad. The point to this whole thing is, though, that you really have to try to grasp the concepts behind the whole thing, not the words or definitions or whatever. It’s what a person
means when they say something that matters.