If the reference is before the Great Schism (1054 AD) it would also include those Churches which are now known as Eastern Orthodox. Thus it would mean -- in the first millennium--- every Church in Christendom.
It can be pretty confusing, even if one is trying to be precise, because "church" is used in different senses by different people. For instance, in Catholicism, "local Church" = "Diocese."
In our own documents, we don't use the word "Church" for anyone outside of the above-described communion; and yet -- and yet --- St. Gregfory of Narek was just his year named a "Father of the Church" (Catholic Church, that is) although this 10th century pre-schism saint was neither (legally) Catholic NOR Orthodox, but a member of the Armenian (Oriental) Church.
That had a lot of people scratching their heads.
As I understand it, his theology and practice were "Catholic" --- he did not have any schismatic or heretical beliefs --- and thus he's de-facto Catholic, though not "juridically" (legalistically.)
Since Baptism is the sacrament by which one enters the Catholic Church, we regard you, R2Z, as being Catholic, too, if you are baptized. No matter who did the baptizing.
Sorry, that's just the way it is. :o)