What do you mean knitting wasn’t present in the roman empire? That’s slightly less absurd than saying knots didn’t exist in the bronze age! Lack of evidence doesnt mean it’s not present! There’s lots of things we know for sure happened during the roman empire despite no one writing about it, like child baptism in early christianity. We don’t know what it looked like, but we know where it happened and that everyone was in agreement about the method.