As it's been a football weekend, I rather than be distracted by a new show, rewatched
Harem in the Labyrinth of Another World
For the fights and fanservice.
As there was a couple of posts about Isekai recently, I thought I'd read up on the subject.
You could argue that the first anime was about 50 years ago and the earliest English language stories about 160 years ago.
I hadn't previously connected them but I suppose Alice in Wonderland, Peter Pan, Narnia, Oz and John Carter of Mars (1865 to 1910) would be some of the first. A Super Mario game was Isekai.