What happened to flags on 15 June
2 flags in the atlas carry this date. The sentence under each one is where that is written down, in its own article.
- Denmark 1219
Now, the flag is falling from the sky in the Battle of Lindanise, also known as the Battle of Valdemar (Danish: Volmerslaget), near Lindanise (Tallinn) in Estonia, of 15 June 1219.
From Dannebrog on Wikipedia, as it read on 2026-08-29
- Latvia 1921
The Latvian national flag, together with the national coat of arms was officially affirmed in this format by a decree of the Constitutional Assembly of Latvia passed on 15 June 1921.
From Flag of Latvia on Wikipedia, as it read on 2026-08-29
How a day gets onto this site
A flag is here because a sentence in its own English Wikipedia article puts it on this date, and that sentence is printed above. Nothing was worked out from a year, and nothing was written for the occasion. Every sentence names the article it came from and the version of that article it was read in, so you can go and check it.
The calendar is still short rather than full. A third of the year has no page here, because a flag only gets a day when a sentence in its article puts something on one, and plenty of articles never do. Nothing is invented to fill the gap.