what happend to the first and second hokages in the naruto series?

[duttonsnake]

When orochimaru summoned the first and second hokages to fight the third hokage he(the third hokage) says that they look exactly as he remembers. This implies that when they died that looked as they did in the fight and any other time they are seen in the series. So my question is what happend to them? Did they die? get captured? leave and never return? Any info would be greatly appreciated.