The culture of flying flags dates returned centuries, serving as a means of communication on battlefields

https://charlie-wiki.win/index.php/Seasonal_Flags:_How_to_Honor_Each_Time_of_Year_with_Meaningful_Displays

The tradition of flying flags dates returned centuries, serving as a method of communique on battlefields. They conveyed messages of allegiance and victory, allowing armies to coordinate actions and processes with out verbal communication.