What a mystery! I know you're hooked 🦂

I don't doubt that he could have said this but I'm not the only one who has been unable to find a source for this quote.

This is going to require further research, and maybe even an attempt to contact Sommers myself.

Of course, Sommers could have retroactively made the decision to make them two different characters.

The problem is that I cannot find an original source for the director making this claim; it only appeared in the past couple of years on Wikis and in forums.

However the people behind the first prequel, The Scorpion King, absolutely believed it was the same character. Here is the Rock, and producer James Jacks, discussing it in the movie's featurette:

Sommers is supposed to have stated that the two characters cannot be the same because he didn't believe such a heroic man could transform into such an evil villain.

This is fair. I've made the same point myself numerous times.

Today, however, I read something I hadn't noticed before.

Apparently, people are saying that Mathayus from The Scorpion King prequels is the grandfather of Mathayus from The Mummy Returns. This fact, evidently, comes from the director of the latter Stephen Sommers.