In the first instalment of the Legends of Star Swirl series, Star Swirl sets out into the dangerous and unmapped sections of Equestria to retrieve the dust of an ancient creature known as the Grand Phoenix, in order to brew a potion which may well save society as everypony knows it.
I was thinking that he already had an assistant in Clover the Clever from Hearth's Warming. Since that was pre-Equestria, and he is now living in Equestria, I'm thinking that Clover the Clever was already his assistant before now.
Oops! Thanks for pointing that out! If you know a website with info on pre-Equestrian history I'd be grateful if you pointed me to it. Gotta make sure that I don't make sloppy mistakes like this again!