The custom of flying flags dates to come back centuries, serving as a method of verbal exchange on battlefields

https://elliottfvyh176.valoradigest.com/posts/stars-stripes-and-school-policy-when-values-conflict-who-should-have-the-final-say-parents-or-educators

The lifestyle of flying flags dates back centuries, serving as a way of communication on battlefields. They conveyed messages of allegiance and victory, allowing armies to coordinate pursuits and systems without verbal conversation.