As a part of my new reenactment company, I need to present proof of each clothing piece. I'm left with my cap and hood to find, since I wasn't able to find any proof of a fishbone pattern. Was it a mistake from me to sew something before checking, or is there any proof of it?
I'm a bit rusty on this, but hopefully this may be helpful. Also I'm going to assume you mean this pattern, which is also known as herringbone or broken twill weave.
In terms of textiles, the herringbone pattern first emerged in Ireland around 600 B.C. One of the oldest known/famous examples of herringbone fabric is the Shroud of Turin.
Examples of surviving medieval herringbone twill fabrics are rare. Here is an example of a surviving twill-weaved linen (link) from the 14th century that was later painted.
Most of what I remember from pre- and early Renaissance twill weaves is that they generally followed a 2/2 pattern when using wool - so diamond patterns and pebble weaves (see: Halvorsen #5 Pebble Weave).