I think the tag “Shoujo” should be added to the section “Genre” of the manga “Utae! Erinna” since it’s a historical series that, while it deals and shows the misogyny of Ancient Greek culture, it has a warm ambience and its main themes are that women love creating poetry and literature and can be great poets and writers as men do, the role of music and performance in Arcaic Greek poetry and the happiness that comes from female friendships and succeeding in your dreams, along dealing with female bisexuality and lesbian love in the subtext. It has entire paragraphs explaining costums, history and mythology that are common in works destined to educate teens on precise topics. Also, it has a softer and kinder atmosphere compared to the author’s other historical manga, “Anna Komnene”.

It is not a shoujo because it does not come from a shoujo magazine. As simple as that.