End of the 13th century
France Lausanne, Bibliothèque Cantonale et Universitaire
U 964 - Biblia Porta fol. 240r
While it is likely that most of the striped garments of the 13th century had woven stripes I thought that maybe, just maybe, when there was just one stripe, or a few, but placed at uneven intervals, as on the man's tunic, they might be embroidered. Or applied from another fabric, but I'm going with the embroidery theory here ;) Since her stripe has the same background colour as the rest of the gown.
So, I have started the embrodiery. In chain stitch, which isn't typical of the period, but my split stitch doesn't produce half as nice results.
There will two double stripes like this, maybe 10-12 cm apart, and then something inside that, haven't made up my mind yet. But fleur-de-lys are always nice. Like Edward the Confessor. Whose tunic surely is made from patterned silk.
Edward the Confessor, from "Life of Edward the Confessor"
13th century manuscript at Cambridge University Library
I am also justifying the embroidery with the fact that embroidery on wool was rather common for interior decoration. Imitiating the patterns of brocaded silks in a cheaper technique is at least palusible, especially since we know that brocades were imitated in other ways, such as printing. Though probably mostly for interior decaration purposes, since the paint would have made the fabric stiff. The preserved printed fabrics are either on linen or silk (or printed cottons from India, but I'm talking about European production here), I have not seen printed wool fabrics mentioned before the 18th cnetury, but I would love if anyone of you have found it somewhere earlier - it really isn't my area of expertise.
Also, since we know of embroidered bands at the hem, it wouldn't be so far fetched to make one a bit higher up.
But, as as said before, most were undoubtly woven, in the first link above you find several preserved examples, and there are also lots of documents from medieval Flanders dealing with the production of striped cloth.