IDK if you know, but Luther, though I disagree with him, saw the Reformers as the continuation of that Church, and saw the Catholics as breaking off from the original Church.
It's not that the Catholics broke off from the original church...
it's that they wandered from it...doctrinally.
and it happened early on.
I won't read any early theologian after the 200's.
The very early ones, taught by the Apostles, are worthy to be read.
If they all agree on a particular topic, you could be sure that it's what the Apostles themselves taught.
And,,,what they wrote about is in line with scripture - of course.
I think it's wandering again right now...
but that's a different topic.