I’ve recently been working through Eusebius and thought I might pass along a bit of advice that might help you. Eusebius is fond of separating the article from its noun and nestling a phrase inside. Take 5 Eusebius 16:3 for example:
Ἐκ πλείστου ὅσου καὶ ἱκανωτάτου χρόνου, ἀγαπητὲ Ἀυίρκιε Μάρκελλε, ἐπιταχθεὶς ὑπὸ σοῦ συγγράψαι τινὰ λόγον εἰς τὴν τῶν κατὰ Ἀλκιβιάδην λεγομένων αἵρεσιν,
Let’s begin by rearranging a little.
ἐπιταχθεὶς Ἐκ πλείστου ὅσου καὶ ἱκανωτάτου χρόνου ὑπὸ σοῦ, ἀγαπητὲ Ἀυίρκιε Μάρκελλε, συγγράψαι τινὰ λόγον . . .
Having been urged for a long and sufficient time by you, beloved Avircius Marcellus, to write a certain word/treatise. . .
That was . . easy . . . But here is where things get a bit tricky.
εἰς τὴν τῶν κατὰ Ἀλκιβιάδην λεγομένων αἵρεσιν
What are we to do with τὴν and τῶν?
εἰς τὴν τῶν κατὰ Ἀλκιβιάδην λεγομένων αἵρεσιν
τὴν goes with αἵρεσιν. Everything in between τὴν and αἵρεσιν modifies the prepositional phrase εἰς τὴν αἵρεσιν. Our translation now reads:
Having been urged for a long and sufficient time by you, beloved Avircius Marcellus, to write a certain word/treatise against the heresy . . .
We still need to decide what we are to do with τῶν.
τῶν κατὰ Ἀλκιβιάδην λεγομένων
τῶν is the article of the participle λεγομένων. Everything in between serves to modify τῶν λεγομένων. Our translation now reads:
Having been urged for a long and sufficient time by you, beloved Avircius Marcellus, to write a certain word/treatise against the heresy of those who are called. . .
Finally, we have κατὰ Ἀλκιβιάδην. Our final translation looks like this:
Having been urged for a long and sufficient time by you, beloved Avircius Marcellus, to write a certain word/treatise against the heresy of those who are called according to/after Alkibiaden.
If we were to rearrange the Greek to make “more sense” to us, it would look like this:
ἐπιταχθεὶς Ἐκ πλείστου ὅσου καὶ ἱκανωτάτου χρόνου ὑπὸ σοῦ, ἀγαπητὲ Ἀυίρκιε Μάρκελλε, συγγράψαι τινὰ λόγονεἰς τὴν αἵρεσιν τῶν λεγομένων κατὰ Ἀλκιβιάδην
I hope this was helpful. Happy translating!
ἐνθύμησις 
I may be showing my age here (the fossil that I am), but my generation used to cite Eusebius as, say, HE 5.16.3. I like your system better, but to which style sheet does it conform?
I am most certainly showing my lack of experience. My Accordance module adopts that citation method. Since this is the way I have become accustomed to looking up references in my text, I didn’t think twice about the style sheet. In print, I believe I have seen it cited as you have it above.
Thank you!
I’ve noticed that this often happens in 1 Peter as well.