The discoveries continue. Northeast of Ieper, is the town of Westrozebeke. Ieper is also spelled, from old French, Ypres -- the town that was Wipers to my Canadian army uncle in WWI. Hello, Uncle Len.
A woman as standard bearer. In Westrozebeke, in 1381, a battle ensued between the Flemish and the French. The Flemish battle standard was borne by a woman known as Big Margot, see page 455 of the Oxford Encyclopedia of Medieval Warfare. It appears that the Flemish were upstart commoners, against noblemen of France, who were ruling at the time. Is that so?
Big Margot fell at the battle, also called the Battle of Roosebeke. That battle is described briefly but she is not mentioned that I could see, at The War in the Low Countries.
Women in war: Not unusual, and even taught in bastions of male techological education, now including female, see https://history.mit.edu/subjects/women-and-war. Women's initiatives for themselves occurred openly until forbidden, and when a role of obedience substituted for them instead. See
Women and Religion in Old and New Worlds, edited by Debra Meyers, Susan Dinan 2014 at pp.75ff. See alsoWomen in Froissart : their role in society and the Hundred Years War, Froissart as a chronicler of events of medieval times, see https://www.hrionline.ac.uk/onlinefroissart/ /
Women bearing arms, who and why: find more, including women in the Hundred Years' War, the Hussite Wars, Sichelgaita of Salerno, Italy (middle-aged, mother of 10) who took up arms later in life, 1076 life, see http://www.naplesldm.com/sichel.phpand a bibliography at the Oxford site above.