The ensign of Denmark is one of the crucial oldest country wide flags still in use these days; featuring a white cross on a red

https://blogfreely.net/neisnenvgb/the-story-behind-the-stars-and-stripes-a-deep-dive-into-american-flag-history-hvbn

The ensign of Denmark is one of the oldest country wide flags nonetheless in use as we speak; featuring a white move on a purple background is known as Dannebrog dates back a minimum of to the 13th century as an emblematic illustration.