Odan-Urr Grandmaster?
Yes, yes, the concept as it exists now didn't technically exist to my knowledge back when he was introduced.
That being said, he was the Head of the Jedi Assembly, which functioned in the same capacity as the Jedi High Council that came after it IIRC. The High Council itself being led by both Grandmaster and the Master of the Order.
So, does Head of the Jedi Assembly = Grandmaster?
Especially given we have references to the title of Grandmaster existing well before Odan-Urr's era in the form of Biel Ductavis, I sort of figure we can infer that's what Head of the Jedi Assembly translates into given the concept was introduced and described after Urr was conceived as a character. :hmm