Norse myths?Then Thor should have said "The last time I came to Earth..." or "On my previous visit to your planet..."
why does everyone assume Thor had been to Earth before.
Sure that, plus what Fandrall said in 'Thor' plus Thor seemed to recognise he was on Earth.
Plus I doubt the ancient Norse would revere Thor as their god of thunder through second hand accounts. I mean, how often do you think a visiting Asgardian would sit down to chit-chat with the mortals about the latest gossip from Asgard's royal court.
Oh, and then there's this.

Does anyone think for a second that Sif and the warriors three went to earth without Thor?