Longsword scabbards - historical accuracy

Hello everyone. Even if the center of this sub are the swords, I always ask myself of the scabbards that are being sold are actually historically accurate, or are a modern reinvention.

I have done some research but i could not find any pattern. I could find the way they were carried in old drawings and some books, and as for the materials and manufacturing processes i could not find too much.

I'd say that a leather-only scabbard for a longsword may be not enough.

Do you guys have any good source of information about this? Or knowledge?