Four minutes is not ages --- and Sideous and Palp. both were pretty much the same voice/actor, and Sideous looked like the emperor, and Palp. becomes the emperor, so put two and two together... in EpII there is a scene with Anakin and Palp. together, "I can see you are becoming the greatest of all Jedi, more powerful than Master Yoda even." Just a bit of a hint of the conversion to the Dark Side that he's trying to do for Anakin.
The Databank on the SW site has this.
Palpatine instituted a military build-up unprecedented in galactic history. He created the New Order, a Galactic Empire that ruled by tyranny. The Jedi Knights, his biggest threat, were extinguished by his greatest dark side pupil: Anakin Skywalker, who had become Darth Vader.