Any trilogies where the first film is the worst?

Interesting to start off a franchise weak, but any trilogies come to mind where the first film is actually weaker than it's sequels?

Rise of the Planet of the Apes is the first one that comes to mind.

I'm not sure if it counts, but I would say X-Men Origins: Wolverine is the weakest of the "Wolverine Trilogy". Other than that, I would say Evil Dead is weaker than Evil Dead II and Army of Darkness.