Wrong again. Stop getting your facts from cartoons.
No it wasn't forgotten and yes it was passed on. What you are quoting as fact is a complete myth.
A modern day myth.
Almost no one in recorded history ever believed in a flat earth. The myth of the flat earth was stuck in our history books due to Irving in the 1800's writing that flat-Earth churchmen had opposed Columbus on the grounds that he would fall off the edge of the Earth if he tried to sail across the Atlantic.
That was made up. It became a modern day myth.
It wasn't even believed even in Irvins time, it was only started to be believed when people arguing on Darwins side bought it up as fact, they used it as propaganda to show how people were once wrong. Like you are doing it now
They used it to back up their argument that Darwin was right, but it was propaganda that they knew not to have been true. (unlike you who doesn't know any better)
AGAIN. Almost no one in recorded history ever believed in a flat earth. It is a modern day myth. What we call in the UK "An old wives tale"
It is what uneducated idiots say when they are trying to back up an argument. But No, it is wrong. No no one ever believed the world was flat. No one.
You are wrong.