Do you find Thucydides hard to read in Greek?

In Nick Nicholas’ answer to Are there any dialects of Greek that Nick Nicholas can’t understand?, I just exclaimed:

I can kinda understand Attic, but I will sneak peeks at the dictionary when I don’t think you’re looking, and I ain’t touching no Thucydides.

So. Let’s touch some random Thucydides. 6.30.

μετὰ δὲ ταῦτα θέρους μεσοῦντος ἤδη ἡ ἀναγωγὴ ἐγίγνετο ἐς τὴν Σικελίαν. τῶν μὲν οὖν ξυμμάχων τοῖς πλείστοις καὶ ταῖς σιταγωγοῖς ὁλκάσι καὶ τοῖς πλοίοις καὶ ὅση ἄλλη παρασκευὴ ξυνείπετο πρότερον εἴρητο ἐς Κέρκυραν ξυλλέγεσθαι ὡς ἐκεῖθεν ἁθρόοις ἐπὶ ἄκραν Ἰαπυγίαν τὸν Ἰόνιον διαβαλοῦσιν: αὐτοὶ δ᾽ Ἀθηναῖοι καὶ εἴ τινες τῶν ξυμμάχων παρῆσαν, ἐς τὸν Πειραιᾶ καταβάντες ἐν ἡμέρᾳ ῥητῇ ἅμα ἕῳ ἐπλήρουν τὰς ναῦς ὡς ἀναξόμενοι.

“And after that, it already being the middle of summer, the going up took place in Sicily.”

Well, that wasn’t too bad.

Ah. The next sentence is 55 words long. I see what they warned me about now.

OK:

“So, of the allies, to the most and the wheat-loaded boats and the ships, and whatever other preparation followed together, beforehand it was said to gather in Corcyra so that they would go across, to the massed ones, onto furthest Iapygia, across the Ionian Sea: but the Athenians themselves, and any of the allies that might have been present, descending to Peiraeus in a strict day together with the dawn filled the ships as loading up.”

I mean, there’s enough bits of meaning that I know what’s going on: most of the allies and the supply ships were to head off en masse to Iapygia, while the Athenians and any allies already there would fill up the ships in Peiraeus by dawn. But what those datives are doing in the start of the sentence, I have no idea (“with regard to?”): there must be a subtle way in which the sentence is hanging together, but I can barely see it, and I can’t read it: I can only gather the bits together, dump them, and guess at the context.

So, how did I do?

Thucydides, The Peloponnesian War

After this the departure for Sicily took place, it being now about midsummer. Most of the allies, with the corn transports and the smaller craft and the rest of the expedition, had already received orders to muster at Corcyra, to cross the Ionian sea from thence in a body to the Iapygian promontory. But the Athenians themselves, and such of their allies as happened to be with them, went down to Piraeus upon a day appointed at daybreak, and began to man the ships for putting out to sea.

Oh! So the “of the allies” depended on “to the most”: “to most of the allies”. Didn’t see that one. And the datives are the indirect object of “it was said”: “it was said beforehand to most of the allies”, i.e. “most of the allies had been commanded”. OK, missed that completely. And I got taken in by “spoken (day)”, which I thought had already picked up its modern metaphorical meaning of “strict” (from “explicitly spoken”): no, it was “spoken” as in “prearranged, nominated”.

I can see how that meaning arises from Thucydides’ passage; I might pick up meanings like that with practice. But I have no practice. And that was likely not even a particularly complicated sentence.