What historical events come closest to "alien contact" when formerly isolated peoples interacted for the first time?

Long story short- I've been having a discussion with a friend that essentially boils down to not needing to come up with conspiracies / ungrounded theories regarding potential extraterrestrial contact with earth (all theoretical for shits and giggles).

My stance is that there have been countless examples throughout history that might as well have been "alien contact" for the people that experienced them. In the sense that the culture, tech, beliefs. etc. that one side would bring would appear "alien" compared to what the norm was for the other. E.g. Sea people appearing announced and disappearing mysteriously, technology being shared between nomadic people, one invader showing up with gun powder, etc.

My question is are there any other noteworthy events throughout human history that could fit into this idea of "alien contact" between two distinct groups of peoples?