Origin of the name Galbatorix

Question

King Galbatorix is the main antagonist of Inhertiance cycle, the high fantasy series written by Christopher Paolini. Was his name entirely made up by the author or does it have roots from real-world languages (for example Murtagh is real anglo-saxon name)? The only historical figure with a partially similar name is a Gallic king Vercingetorix (https://en.m.wikipedia.org/wiki/Vercingetorix)

Answer 1

Galba is a celtic king in the 1st century BC. Wikipedia states the name means "fat" and might have connotations of prosperity.

-rix is a celtic name suffix meaning "ruler".

I would assume Galbatorix might come from these two ingredients.

Answer 2

The name is derived from the Celtic words for "big king".

The first quote I can find is from a 2003 article, which gets the gloss of "big king" correct, but the interviewer seems to confuse it with the ancient language and so says that it is Old Norse.

Eragon is steeped in quotations: every ingredient, from dwarf to elf, from the brilliant blue stone of the dragon's egg to the old sage with the long white beard, is a stylised cliche. Ask him about Eragon's villain, the wicked emperor Galbatorix, and he will cite Darth Vader of the Star Wars movies because, like him, Galbatorix started off "good" - a Dragon Rider - and turned to the dark side of fear and power. "His name, of course, comes from the Old Norse. It's a rough translation, but it means big king," Paolini adds without a blink. Old Norse is the basis for elfin language in his book.
_{The Telegraph, London - October 2003}

Shortly after that, there is this quote from a 2004 online collection of Q&A's from Christopher that his mother had edited together.

[Some of my character names] are derived from real languages, such as Old Norse, German, Old English, and Russian. Galbatorix, for example, is from Welsh. Torix means king and galba means big. Thus he’s the big king, which works perfectly.
_{April 20 2004 Interview Compilation}

More recently, this was said in the 2018 collectors edition of Eragon, which included a bonus section in the back going through the origin of many names.

Galbatorix: Galbatorix is a combination of the old Celtic words galba ("big") and rix ("king").
_{Eragon Barnes & Nobles Exclusive Collector's Edition - "Names"}

And then in a reddit comment, Christopher corrected a mis notion that the meaning was meant as an in-universe translation, and clarified that this was purely an out-of-universe inspiration

[T]he name "Galbatorix" is not from the ancient language. The meaning of "big king" is actually from the real world and is a nice nod toward his role and journey.
_{Reddit - June 2022}