The only canonical hard information on this Heterodyne ancestor of Agatha's comes from the description given by Maxim during his fight with Ol' Man Death. Apparently, Prince Vadim Sturmvoraus bet the "Goot" ("Good") Heterodyne that a cathedral could never be built in Mechanicsburg. This resulted in the construction of the Red Cathedral, and Vadim having to eat his hat.
According to the tale which Baron Wulfenbach for Phil the storyteller, old Goot's birth name might be Gradok the Dour, but since that entire story was pretty clearly a coded message aimed at Gil, any historical information it offers should be considered dubious at best.
The print novel Agatha H. and the Voice of the Castle gives Goot's name as Dante, and says that he was called The Good Heterodyne not from nobility of spirit, but because he was very good at being a Heterodyne.