OK, nevermind. I figured it out on the Starwars.com databank.<br /><br /><font color="yellow"> When Yoda was 700 years old, he served on a council of Jedi Masters instructing new students aboard the massive Jedi training vessel Chu'unthor. The starship crashed onto the planet of Dathomir. The Jedi Masters attempted to free the vessel from its swampy confines but they were repulsed by the Dathomirian Nightsisters.<br /><br />Much of Yoda's history is unknown. Just prior to the dark times that accompanied the fall of the Republic, Yoda trained the Gannathan royal King Empatojayos Brand in the ways of the Force. Another student of his was the powerful and stern Qu Rahn.<br /><br />Another tale of Yoda's past involves stopping a swath of destruction cut by Dark Jedi from Bpfassh. One of these dark siders had gotten as far as Dagobah, were Yoda bested him in direct confrontation. The Bpfasshi Jedi died, his dark Force absorbing into and twisting a nearby tree -- forming a dark side nexus. It is believed that Yoda chose Dagobah as his hiding place due to the dark side energies emanating from the tree. From a distance, Force-users like the Emperor would not detect Yoda since the master's bright light side presence would be canceled by the Bpfasshi dark side presence.</font><br /><br />As for being canon or not, that is Star Trek, not Star Wars. From what I heard all the authors had to clear everything with Lucas first.<br /><br />Of course the time line still doesn't make sense.