In the note family because the breves last for the longest time, they would be like Great-grandparents in a human family.
Not many people have living Great Grandparents today.
Not many composers use breves in today’s music.
You may never see a breve in the written music you use.
And now you know why a double-note is called a semi-breve.
A breve (double -note) could look like this as a family face.
Musicians gave the breve a head with this shape.