The idea of Medieval infantry wearing the “colors of their lord” is mostly a myth, as for one most medieval infantry weren’t part of a retinue of a “lord” as for example in England most soldiers were directly hired by the crown through a contract system called “indentures” and thus they had no need or reason to wear the “colors of their lord” and in Germany most soldiers were mercenaries. Instead of uniforms medieval infantry and knights as well wore “field signs” you can see it in the original image that Op posted. As you can see the English soldiers are wearing red crosses and have worn em since the 1200s and French as well as the Swiss began to use White cross since the Hundred Years’ War. Sashes we’re used as well, For example the Spanish wore red sashes in their war with the Dutch, and the Dutch began to wear orange sashes. That’s to say no soldiers during this time period wore “livery colors” as it certainly did happen but it was mostly a English phenomenon during the wars of the roses, when local magnates began to build private armies. And thus relatively unheard prior. Field signs were standard amongst most armies for identification