From context, it is clear that the Wizard Titles are a ranking of relative power. After all, you typically start as "Average" in most games. It seems that "Magnificent" is the highest, but where do popular, famous, great, and powerful fall on the spectrum?

I've been using this forum:
http://aow2.heavengames.com/library/strategy/
for pllayer guides, but I did not find an answer to the above over there.

Your power title comes from your fame combined with your relative strength. Magnificent has greater than average strength (your strength is 1.25 or higher than the average) and high fame. Titles change as your fame gets lower and/or your strength compared to the average gets lower.

Thank you both for your replies. Have downloaded the manual.