So, I'm an amateur who is currently reading Herodotus as my first step in my burgeoning classical history hobby, and I'm curious to understand if modern historians have a different understanding of how the line of Cyrus came to an end and how Darius ended up taking power. I know that there'd necessarily be a lot of conjecture to this, but I'd be interested in hearing what anybody has to offer as an alternative to the horse-vulva tale.

I have plans to read Briant as a more contemporary resource to the history of Achaemenid Persia in the near future, but I'm an impatient such-and-such...

As an aside, Darius actually strikes me as being a lot like Augustus, personality-wise: both of them seem to be simultaneously the most utterly shameless, ruthless cynics whose version of events are still commonly believed because they happened to be best propagandists of their age... and also the most genuinely fervent, pious restorers of their old-time national values and honor as they saw it, restorers of sorts. Dunno if that's a stupid comment, but there you go.