I wonder if the first nation to have a song that was labelled as a national anthem was the US? Before theirs was adopted, there were lots of songs for political causes, but it took a while before anybody thought of nation-states as being causes that needed their own songs, still less official ones.

In a lot of places you get disputes about whether the official rallying song of a liberation movement that played a large part in bringing a nation-state into existence should be the national anthem afterwards or not.