I have a vague memory that they specifically said 1630 early on, like in the opening title of the opening episode, and then left it at that and haven't mentioned it since. I'm really weak on French history, though, so I wouldn't be able to tell you the difference between events of 1625 and 1636. But that goes back to what I was talking about using historical fiction as your source material. There are SOME limits--I mean, I don't want to see Daniel Boone show up in a target shooting contest with the Musketeers or something--but I'm willing to cut them a lot more slack about "accuracy" when the whole thing (exceot for a few secondary characters) was made up from scratch to begin with, and everybody knows that.
Of course, that attitude could stem from my ignorance and I might care a lot more if I knew a lot more. In the mean time, those Czech palaces and backstreets look awfully good.
I do like that the whole premise of the show is in its title: "The Musketeers." Not "The Three Musketeers" ("but there's four of them!" I remember thinking as a child), not "The Young Hero D'Artagnan and His Sidekicks," but "An Ensemble of Swashbuckling Musketeers."
Ah, but one thing to bear in mind in these days before DNA testing is the possibility that Louis really IS the father. Because this non-doltish Louis knows how to count backwards from nine and surely Anne has enough sense to let her husband near her for insurance sake, if nothing else. Given that Anne did get pregnant earlier, it's quite possible his little swimmers may have outraced Aramis'. Not saying it's likely or that it actually happened, just that ambiguity, not certainty, should be the order of the day with these things.