So I'm pretty sure that Hiruzen was Hokage for a long time, a span which included when he was sensei to the Sannin.
That makes sense (though my initial thought was that Hiruzen was named to Tobirama's team BEFORE Tobirama became hokage -- as it appeared he was Tobirama's student when Hashirama was still alive (and thus still the first Hokage), so the 2nd Hokage having a team might have just been an artifact of having become a teacher before being named to the position, so I'm not sure how much of a precedent it is as Hiruzen first took on the Sannin AFTER being named Hokage. Hm), and is pretty much the way I figured it, too, but I wanted confirmation first -- there have been a few sections of the manga that I've skipped (in favor of summaries) or merely skimmed through, and there's always a chance that something that feels "unlikely" like that might have been explained in a part of the manga I haven't read quite as thoroughly.
(Incidentally, does it ever feel to anybody else as if Konoha's history is too compressed? It feels like there should be no way that the Sandaime was only 69 years old when he died, as the databooks claim -- he would have been alive and acting as Hokage throughout most of its existance, while the First and Second are supposed to have pretty big legacies, themselves, that would suggest equally long reigns, but it seems as if they were only running Konoha for about 5-10 years, each, at most)
Edited by desaix, 01 December 2012 - 09:16 PM.